How to Prank someone by changing their cell phone numbers

If you want to cause one of your friends some extreme discomfort and possibly ostracization, try doing this to them! This video will explain a simple prank that you can pull when one of your friends / enemies leaves their cell phone unattended in your presence. I won't give it away, but they are sure to feel the wrath of this one and will not be able to blame it on your concretely. Brilliant!