If I don't like how my new strings play, I re-tension it, instead of cutting it out. To untie the knots easier, I use what I call a 'shoe lace' knot. Do a normal half-hitch knot but don't completely tighten at this point. Leave a hole. Insert the tail back into the same hole. Now you have two strings occupying the same hole, forming a loop Pull the inner tail to tighten it (I use a starting clamp). After tightening the knot, pull the tail to reduce the loop as small as you can Pull the tail under the anchor string, then up and insert into the loop that you created earlier. This will prevent un-tying the 1st half-hitch. Tighten. I usually leave an 8" tail on each knot to allow for re-tensioning/tie-off. See pictures for visual details: https://goo.gl/photos/YiQWapdP8jfh7Me88 The 2nd knot is easy to untie, especially if it is a poly or monogut zx strings. I just push back the tail into the knot to loosen it up using a long nose pliers. To untie the first knot, it is as easy as un-tying your shoe laces. Just pull the tail and the knot is gone. I don't notice the strings losing tension or loosening up because of the 'shoe lace' knot.