Originally Posted by
IslesFan
Easiest way is to have a second iPhone that supports eSim on your iCloud account. Active the second eSim on that phone, and then under settings -> cellular -> add cellular plan transfer it from the old phone to the new phone.
This.
To piggyback on the procedure, you can use a physical sim card to do the same thing. Your iPhone 13 will import a line from a sim card in another esim capable iPhone on your account and convert it to esim on the new host phone. Bada Bing, you would then have 2 T-Mobile esims on the same phone with only 1 IMEI. I tried to use my on line account manager for the second esim import and it wouldn't work. I then contacted 611 first, and then T-Force on Twitter and neither said they could do it. Their reason was their was only 1 IMEI, and it was already in use.