It needs to be possible to undo an accidental ticket merge properly. Currently, you can change the status of a ticket from Merged to Open/Pending to get it back, but it will be empty and the contents still on the ticket which it was incorrectly merged into.
This needs to have the original contents remain on the ticket and REMOVE those contents from the one they were merged into - they presumably haven't been sent to the contact who had the original ticket so it's not destroying a "paper trail" but deleting the contents from the original ticket which got merged IS.