If you want to remove an account from the account selection screen that you see when you login into the game, follow these steps. Please note that you are only able to remove accounts from the account selection screen if they have a verified email attached to them.
1. Log into the profile you want to remove. Then, make your way to the settings button. You can find this button by opening your watch menu, and then clicking on the settings icon on the top right.
2. On the next screen, select the "Advanced" tab and you should be able to find the "Remember This Account" option. Unselect that option. The account will be removed from the account selection screen.