You have to create a new account for them and report their information under their new account.

See instructions

1.       Sign out of TurboTax Online.

2.       Select the TurboTax Online product you want to use for the second return and proceed.

3.       On the Create your account screen, set up a new login for the second return.

o    You can reuse your email address if you want to receive e-file notifications for the second return.

o    Up to 5 accounts can be tied to the same email address.

4.       After you've created the new account, you can start working on the second return.

Tip: If you're preparing multiple returns for family members, it's more economical to switch to the TurboTax CD/Download software, which lets you e-file up to 5 federal returns at no additional cost. More info