Only super-users have the right to recall a proposal (SPO staff are all super-users).
Click the recall button:

Then CLOSE the proposal/record. You can't edit it until you close it and re-open it.
Search for the proposal (Lookup the number) and click the "edit" link in the results:

Now you can edit it. Once you've finished revising the record, check the route log to see if any Ad Hoc recipients need to be added back again, and then click the [Submit for Review] button.