Hello. Even in the corona disaster, I am the project leader of the railway Daisuki Syndrome, Sugapi.
It's sad that I can't get on the train far away, but there are various railway content in the wide online world, so I'm enjoying it. I want to return to a world where events can be held as soon as possible.

Image source: Wikipedia
In such a situation, the image above is the "TH Liner" that started running on the Hibiya Subway Line.
You can sit and commute to work with a reserved seat. Moreover, the seat moves vertically and horizontally, so it can be used as a liner or as a normal liner~. I haven't ridden the liner yet because the stops are limited, but I've encountered it normally. I really like the seats that are separated by armrests.
It seems that it will be difficult to prepare and use it after this corona disaster, but I hope you will do your best.
Company name change! My email address has also changed!
By the way, have you ever changed your company's "email address"?
Colorkrew changed its company name from ISAO Co., Ltd. to Colorkrew Co., Ltd. on June 1, 2020, so it was necessary to change the email address.
▼The company name has been changed to Colorkrew!
But is it okay to change your email address? Various troubles are likely to occur...
I will deliver my struggle that was trembling from the time the company name change was decided until I changed my email address. It's something I rarely do, but it might be helpful to someone.
Take a Domain Name
As soon as it was decided that the company name would change within the company, we decided to secure a domain name first.
「. co.jp" is a rule of one company and one domain name, and ISAO Co., Ltd. has already acquired "isao.co.jp". If this continues, you will not be able to get a "colorkrew.co.jp".
The corporation whose name has changed is the ". In order to continue to have a co.jp, it is necessary to apply for relaxation of one domain name per company. To do this, a copy of the register after the company name change is required.
A copy of the register cannot be applied for in advance because there is no description of the company name change unless the company name has been changed. Therefore, we first applied for "colorkrew.co.jp" as a provisional registration, obtained a copy of the register after changing the company name, and then applied for relaxation. Now you can have both "isao.co.jp" and "colorkrew.co.jp".
In addition, the "isao.co.jp" you already have is registered under the old company name, so we are also going through the procedure to change it to the new company name.
This is because the domain name needs to be able to continue to be used in order to continue receiving the old email address after changing to the new email address.
*Although I actually obtained a "colorkrew.co.jp", after considering various things, I decided to use "colorkrew.com" as the main one.

Consider Your Sphere of Influence
At first, I thought that since it was a company name change, I would only need to change the domain name (@より後の部分).
However, as part of the branding, it was decided to change the account part (@より前の部分) of the email address, and the email address was completely changed.

**Is such a change possible in the first place? **
Since Colorkrew uses Microsoft's Office 365, we contacted support to discuss the scope and method of changing the email address.
The conclusion was that it could be changed and there were steps on how to change it, so it didn't seem to have a big impact.
But is it really okay?
I was interested in the Office 365 sign-in account.
This is the email address itself.
A change in email address means a change in your Office 365 sign-in account, which means it affects everything that requires Office 365 sign-inThat's what it means.
A typical example is all Office apps. Such as Outlook email and calendar, Word, Excel, Powerpoint, Teams, OneDrive, OneNote, etc.
In addition, Colorkrew offers various suggestions in Power BI, and you will also sign in with your Office 365 sign-in account. Even in "Kuramane", which operates and builds various clouds, Microsoft's Azure signs in with an Office 365 sign-in account.
We also operate in the customer's environment, in which case it will be registered as a guest account, so we must make sure that all of these things can be used without any problems by changing the email address.
Therefore, we decided to build a verification environment separately from the production environment and conduct verification there.
Validate
Colorkrew is a Microsoft partner, so we use a partner license to build it as a separate tenant. (Normally, I think it is difficult to go this far due to licensing issues.) )
Now, now that the environment is ready, we will actually verify it, but we cannot use the same domain name as the actual one.
The reason is that it needs to be registered with DNS. Well, you can't send emails to colorkrew.com in two places.
In the validation environment, we obtained a separate domain name for testing the old and new domain names, registered it in DNS, and set it up in Office 365.
Once you have your domain name ready, it's time to prepare your users.
Colorkrew has Windows 10 and Mac users, so we will create multiple test users in Office 365. In case there is a problem in the test, you have prepared multiple so that you can redo it to some extent.
It would be bad if the computer I usually use interferes with my work, so I have prepared a computer for testing with each user.
Then, in order to check the various situations I mentioned earlier, I made preparations in the way I would normally use it, such as creating files, sending and receiving emails, posting and mentioning, and then changed my email address in the verification environment.

Problems and Countermeasures
I was ready for verification, and I actually tried changing my email address and verifying it from various angles.
I was able to send and receive Office apps and emails normally, and I was able to receive them without any problems even with my old email address. From: in the outgoing email, is the new email address.
Surprisingly, there were no problems, so I was relieved.
Past Teams posts were carried over to new users, and signing in to the Azure portal was no problem. The participation of another tenant who is a guest is also properly coordinated, and I realized that the linkage of Microsoft products is also expected to change the mail.
However, as a result of verification, there were times when the synchronization of notes in One Note failed, so I had to sign out → sign in and synchronize again. I guess this means that in a worldwide cloud environment, it takes time to synchronize the entire area.
Just in case, I have created a sign-out and sign-in procedure for each app so that you can respond to inquiries.
Since you will change your email address all at once, if there is a problem, you will be contacted all at once. There is a limit to how much we can respond to each member of the Emotional Sys, so we will do what we can prepare.

Finally change your email address!
The verification is complete, the inquiry response is ready, and it's time to change.
In fact, the company name was changed on June 1, 2020, but the email address was changed on June 10, 2020. At the beginning of the month, emails were flying inside and outside the company due to the previous month's closing and billing, and the Office application was running at full capacity, so I shifted the timing to avoid unnecessary confusion.
The date of the email address change is a weekday morning.
If you take a holiday, you may not notice the problem. This was to allow you to contact Office 365 support if you couldn't solve the problem on your own.
In fact, when I did the change work on the morning of the day, I had the impression that it was not as noisy as expected, and the switch was relatively smooth.
I had some issues with Outlook and Teams, such as not signing in properly when signing in, but the steps I had prepared were helpful, and I was able to solve most of them by signing out and signing in.
However, some of them were formidable, and in that case, the person's Office app was uninstalled and reinstalled to deal with it. After the switch, there were a few places where the "ISAO" notation remained in the Office 365 settings, and they were changed accordingly from the Office portal admin page.
Logo images are also important.

Conclusion
So, although there were some problems that I had expected, I was able to change my email address relatively smoothly overall.
The design of Office 365 and Azure accounts was designed to accommodate email address changes, which I appreciated when I actually had to make a change.
However, it is also true that it is scary to do it without verification at all, so I wish there was a system that could be verified a little more easily... In that sense, I hope that it will be of help to everyone in the world who has encountered the important task of changing your email address in the future.