If you cut it, you will have to replace the topper fabric rather than just re-sewing the seam. But if that's what you want to do... Just cut along the back edge and the fabric rolls up on the tube (quite quickly!).
It's not hard to remove the entire topper if you have a ladder, but having a friend helps. Maybe a neighbor camper?
Former owner of 2004 American Tradition and several other RVs
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC