Yes you can.

To start a new return, select “Start a New Return” from under “My Returns” in the bottom left corner. Once you have started your new return, you can select “View All Returns” from under “My Returns”. Then delete the unwanted return by clicking the small Trash Can next to it or “Delete” under the return’s name.

However, if you already paid for your return, the payment doesn't transfer to the new return, so starting a new return means paying again.