Log into the Admin Portal and navigate to the users tab.
Check to see if the user has a phone. If there is a phone assigned to the user, remove it from the user.
It will be helpful to copy down this information because you will need it later.
If there is no phone assigned proceed to the next step.
Select the user then go to User Settings > Manage Services.
Disable CM Voice Services and Voicecube services.
Remove the number by selecting User Settings > Properties. Then go to option 3 Phone. Change IP Phone to None
From the locations tab select the location where the number is located and click on DIDs > DIDs. Select the DID you are wanting to modify.
Change the DN (extension) to what you want it to be. Make sure this extension is not a number that has already been taken by another person before you change it. Click save when you are finished.
Navigate back to the Users tab and search for the user the DID was originally removed from. (Note: At this time the user has no DID, you will need to search by first name, last name or username) Then click on User Services > Manage Services.
Add CM Voice Service and Voicecube services back to the user. When selecting CM Voice Service back to the user it will prompt you for a phone number. Select the number and hit save.