How do I change or delete the person that used the personal turbo tax last year?

The TurboTax online editions can only be used for one tax return per account and User ID.  

If the account you are trying to access was used by someone else, you need to create a new account with a new User ID for yourself.  

You can use the same email address for up to 5 User ID's with the online editions.

Create a TurboTax Account