I would like to change my Apple ID to a different ID. Only the Apple ID need to be changed and I would like to keep my password. Please help. How do I do that?
How do I change a Apple User ID to a different ID without changing my Password?
Please see Change your Apple ID - Apple Support
Changing the ID to a different email address doesn't change the actual account in any way, though it's advisable to sign out of everything before proceeding and sign back in with the new ID afterwards.