There is a user site that is 3.5 hours one way drive that is having an echo issue on 2 phones. they have 2 phones in offices that are not being used.

they are all registered and have extension numbers.

Is there a way to use the set replacement code to re-register one extension as another?

for example. say 1000 has an echo but 1001 doesn't. I want 1001's phone to be now be extension 1000. I know the set replacement code works when the display says "enter pin" but what about if they are both already registered?