Hi all, apologies if this has been asked time and time again. I searched the NEC forums before posting but could not find an answer. From searching other boards it appears to be a reasonably common question, but the last board I found asked for $$$ for the answer.
Ok, How do I change the names given for extensions on our system? eg: ex employee John's extension to new employee Joe.
Pressing [feature] [3] gives the following info:
KEY SYSTEM
SP335 V5.00
The is also further info on the bottom of the phone if required. I am told it is a NEC XEN system.

Thanks.