Move Epic account to a different Xbox gamer account
Solution 1:
No, you cannot disconnect an Epic Games account from an account on a console and reconnect it on an account of the same console type.
Once you disconnect, you won't be able to connect a different console account of the same type to the same Epic Games account. Example: If you disconnect your Xbox account, you won't be able to add a different Xbox account to the same Epic Games account.
Source: https://www.epicgames.com/help/en-US/epic-accounts-c74/general-support-c79/how-do-i-disconnect-my-console-account-from-my-epic-games-account-a3253