[Cajundaddy]

Using a drill to loosen the old cord is a good idea.

When we used to do them we would use two guys, one on each end and do a push-pull to free it. Once free the old cord can be used to pull the new light cord from the pool side to the J box. Make sure and get this right with all cords, connections, and fixture water tight. Every year a dozen people are killed due to a faulty pool light repair.

Never run power to the light on deck. They get hot super quick and kill all the seals.