migrating app to another Apple ID
I bought X app with Apple ID A and I decided to leave it for Apple ID B.
Can I keep my X app on device with the new account B ? Or I have to buy It again ?
Question marked as
You would need to purchase any media, app, etc. tied to your old Apple ID again.
The alternative is to simply change your Apple ID, not create a new one. Change your Apple ID - Apple Support