It is possible to cancel an issued reminder directly from the reminder.
If interest was automatically posted then the reminder was issued, this is also canceled.
Let me show you.
I opened the issued reminder.
Go into process, and press on cancel.
Now, I get an option if it should use the same document number or if it should choose the number series that has been defined in my sales setup.
I f I should use the posting date, or if there should be a new posting date.
And I press on ok.
Now, I can see here that the reminder has been canceled.