It's been YEARS and this basic feature still doesn't exist. Players have been asking for this since day one and nothing changes.
Do you even listen to the global community at all? Or do you only care about the Chinese version of the game?
This is basic account management that almost every modern game has. Yet somehow Call of Duty Mobile still can't implement it after all this time.
Seriously, what are you doing? Stop ignoring your players and add a simple unlink account option already.