There is a tricky way to clear out transferred info in the Online version. But doing this will also clear out all your entries. Go into your return, go Tax Tools > Tools > Transfer from your computer > Continue > then Continue without transferring.
Or you can just start a brand new account with a new username.
The Online version is only good for 1 return. But you can use the same email address for 5 accounts. To do another return log out of your account and set up a new account and new user name and pay any fees again. That's why it's better to use the Desktop CD/Download program. The Desktop program can do more than 1 return and efile 5 for free.
How to start another return in the Online version
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-onli...
