Cable ties come in two different varieties: single-use ties and reusable ties. Cheap nylon ties are almost always single-use ties that you will need to cut open if you want to undo them. That means you cannot use the same tie more than once. However, there is a way to reuse single nylon ties. Instead of cutting the ties, you should insert a metal strip or pin inside the locking mechanism and press down. This will disengage the teeth of the tie. While pressing down, slide the tie out of the lock. But doing this for a few times can wear out the teeth, and it will stop working.