Moving valve to another room not detected

I had an old valve that had already been numbered. But I wanted to add it again and it's not recognized. But it already has a number. It has been removed from the list of detected valves... But now it's not recognized as a new one or listed.... How do you reset it? I had problems like receiving valves from a friend and having the same numbers. The system is really bad. We are unable to remove the numbers, or change them.