Hi, Joanne ....
I'm not sure this is possible. CRA receives the e-filed return within moments of submitting it. Not only that but their policy for most returns is to immediately assess them upon receipt. You could try calling the e-file help desk to see if they can nullify it, but I doubt they would do that.
I have also had this happen to me in past years where I've submitted the return, then suddenly realize I forgot to make an entry. In these cases, I've quickly checked the status of the return on Represent-a-Client verifying the return was Assessed on filing, then ReFiled. As long as it has been Assessed, you can ReFile immediately. You don't have to wait for the NOA.
Hope this helps.
