I just bought a used BCD396XT from a friend. It has some San Antonio area frequencies on it. Do I need to remove these and start programming it all over, or can I add my local channels to it? I live West of Houston in the Katy/Brookshire/Pattison/Sealy area. I might add, I don't have a clue how to program this scanner. The last scanner I owned was 20 plus years ago.