There is no way to stop an e-file once it has been sent.
The opportunity to stop the e-file occurs when the e-file submission report is generated. At that time, the preparer will have the opportunity to submit or cancel.
Once the return is sent, it is not retrievable.
There are two options at this time:
If the return is rejected, you will be able to make corrections as needed.
If the return is accepted, you will need to file an amendment.
There is no way for UltimateTax to stop an e-file once it has been sent.