Yes your "original" exposed piece of CPTN is destroyed when you develop it. You can't reuse it. The developer is a highly alkaline developing agent and the peeling apart is in essence your fixing. I remember the developer was good in the tray for a day and in the bottle for roughly a week and then your D-Max was right out the window. Crystal build up in the developer was unavoidable. If you were to develop it by hand you could try using one of those old Kodak print rollers. Soak both pieces in the activator then on a dry surface lay them together and in one stroke only roll the Kodak roller of them both to squeegee them together. Usual dwell time was 60 seconds for CPTN but since this stuff is so old 90 to 120 seconds is probably called for. Don't be disappointed if this stuff doesn't work, it didn't have a long shelf life. It was meant for a production environment and wasn't designed to sit on a shelf for long periods of time.