I'm trying to open up a doorway into my dining room (the current one is just too narrow). I am experienced in taking down and installing new framing and drywall, however there is a baseboard heater that I need to shorten and I'm not sure how. The loss of heat should be minimal. There is another baseboard heater very close by. Do I simply turn off the water supply, remove the metal cover, cut the copper pipe where I want it to end, re-cap the copper pipe, cut the cover so it fits, and then re-attach the cover and turn the water back on? Thanks for any advice.