Hi, @kenny heath
Unfortunately, there isn’t a supported way to move a Minecraft Java license from one Microsoft account to another after it was migrated.
Minecraft account migration ended on September 19, 2023, and Minecraft Support no longer handles migration-related requests.
If you still have access to the Microsoft account you migrated it to, you’ll need to continue using that account to access Minecraft Java Edition.
You can also see Minecraft’s announcement here: https://www.minecraft.net/en-us/article/account-migration-last-call
Should you need further information, please let me know.
Click "Add comment" to let me know.
Thanks!