Hi, I mistakenly checked the box "yes" to the question "do i want to file the return with my spouse". It seems i cannot change that answer. Any solution ? Thanks

You can't remove a spouse from a return. You would have to start a new return and choose that you are only preparing the return for yourself.

To start a new return in TurboTax Online, select “Start a New Return” from under “My Returns”. Once you have started your new return, you can select “View All Tax Returns” from under “My Returns” and delete the unwanted return by clicking the small Trash Can 🗑 next to it (or “Delete” under the return name).