Wait till your acc is 24hrs old. Then link it to a email address or Facebook account if you want to keep access to your account. Then you can log out.
Link account:
Tap cog in top left where the house usul is
Go to account
Tap either ata (to link a email address) or Facebook (to link your Facebook)
Fill in the info
Done
Log out:
Tap cog in top left corner where the house usul is
Go to account
Go to device linking
Tap logout
You might get a pop up saying theres limited amount of times you can do it but the limit got taken away years ago you can log in and out as much as you want
Please make sure you have created a Log-In via an ATA account (email + password), a Facebook connection, or an email link if you ever want to be able to log back into your account.
Accounts can not be logged out of for the first 24 hours after account creation. So if you made this account less than 24 hours ago, you are stuck in it until those 24 hours are up.
I recommend reading the game's FAQ too. (You can also access it via the same menu in step 2 and tapping "FAQ" instead of "Settings.")