Startup Idea : Cell Phone Numbers reservation

People who travel from countries to countries would like to keep their cell phone number that he bought for the first time he bought the pre paid SIM.E.g. An US person needs to work in the UK for 6 months and wants to keep his UK cell number in case he needs to go to work in UK again. Instead of getting a new prepaid SIM (with new number), he can reserve that number he used.Can we create a system (or even a app) or work with phone carriers to reserve the numbers (for a small fee) and release it back when the customer needs it? He can purchase new SIM and tag the cell number to that pre paid SIM he just bought.