Unable to change extensions/activate extension

[businessi]

Hello,

I am currently trying to change the extension for some staff that have changed offices.
For some reason it will not let me change from 122 to 116, any ideas?

 

[NicholasP_3CX]

By change from 122 to 116, do you mean to log in as 116? Or to change the User at 122 to be 116 now?

You cannot renumber an extension that is already created.