If you have not e-filed yet, you can delete and start over by following:
https://ttlc.intuit.com/replies/4248526
If you are trying to fix a return that has already been e-filed:
- If you have already e-filed and it has been rejected, you can fix the issue and e-file again. A return cannot be started over or deleted at this point.
- If you have already e-filed and it has been accepted, you would need to file an amended return if you want to change it (but it cannot be started over or deleted at this point):
https://ttlc.intuit.com/replies/3288565