The Uniden Bearcat BC144XL is a 16-channel base scanner use to monitor several forms of communication such as police and fire department or weather broadcasts. The scanner has a number of pre-programmed channels that are mainly weather-related channels and also gives you the ability to program and reprogram your own selected channels. The process of reprogramming channels on the Uniden Bearcat BC144Xl is same as programming original channels. When you assign a new frequency into a channel already in use, that position becomes fixed to the new frequency. Press the "Manual" button to stop any scanning the Uniden Bearcat is doing. Press the channel number that you wish to reprogram into the numeric keypad, then press "Manual" again. Type in the frequency numbers that you want to program into that channel into the numeric keypad, then press the "E" button for entry.