I removed a 302C and replaced with 9641 and expansion modules. Hope this gets you started in the right direction.
This is from the Administrator Guide for Avaya Communication Manager, p. 194 in my book:
Removing an Attendant Console
Before you physically remove an attendant from your system, check the attendant’s status,
remove it from any group or usage lists, and then delete it from the system’s memory.
For example, to remove attendant 3, which also is assigned extension 4345:
1. Type status attendant 3. Press Enter.
The Attendant Status screen appears.
2. Make sure that the attendant:
--is plugged into the jack
--is idle (not making or receiving calls)
3. Type list usage extension 4345. Press Enter.
The Usage screen shows where the extension is used in the system.
4. Press Cancel.
5. If the attendant extension appears on the Usage screen, access the appropriate feature
screen and delete the extension.
For example, if extension 1234 belongs to hunt group 2, type change hunt group 2 and
delete the extension from the list.
6. Type remove attendant 3. Press Enter.
The system displays the Attendant Console screen so you can verify that you are
removing the correct attendant.
7. If this is the correct attendant, press Enter.
If the system responds with an error message, the attendant is busy or still belongs to a
group. Press Cancel to stop the request, correct the problem, and type remove
attendant 3 again.
8. Remove the extension from voice mail service if the extension has a voice mailbox.
9. Type save translations. Press Enter to save your changes.
Note that you do not need to delete the extension from coverage paths. The system
automatically adjusts coverage paths to eliminate the extension.
Now you can unplug the console from the jack and store it for future use. You do not need to
disconnect the wiring at the cross-connect field. The extension and port address remain
available for assignment at a later date.
You will also want to change listed-directory numbers and remove the extension as your attd is likely assigned the lead DID, and you will remove attd. Then you will add a new station assigned to the lead incoming DID that your console had, build coverage paths, etc.