Honestly, I don't think you can. I've had my system for 6-7 years and I was given a list of available numbers to choose from but I think my local phone company would not transfer my old line. They don't like losing customers. Anyway, it doesn't hurt to ask if it can be done but I doubt it. Sorry. My OOMA system has always worked great. I just got my daughter the newer version of the system for her business. Good luck.