I have a login1 and two users user1 and user2. All three are created previously. Originally, login1 was mapped with user1 and now I want to change to map with user2.
First, I tried
ALTER USER user2 WITH LOGIN = login1;
But SSMS shows
Cannot remap user to login 'login1', because the login is already mapped to a user in the database.
Then I tried
EXEC sp_change_users_login 'Update_One','user2','login1'
The login already has an account under a different user name.
When I search with these error messages, most of the posts are talking about why this would happen or how to identify the related (origin) user?
But my focus is as titled, how can I change from one existing user to another for an existing login? Is it possible to achieve without re-creating any of them?