use utility knife to cut rectangle inside patch
pull off newly made patch
Make a Cut-Out
Once the paste has had a chance to set up, use a utility knife with a new blade and a straightedge to cut a rectangle around the inside of the patched area (Image 1). Cut straight lines to form a neat cutout and avoid overcutting the corners. Once you've made your cuts, remove the portion of excess wallcovering surrounding the newly-cut area.
Then, very carefully pull off the newly-made patch from the middle (Image 2).