In Teams, extensions are assigned to accounts/Users rather then physical devices like the previous phone system. Each user can only have 1 line assigned to them. To have access to a shared line or another user's line, you must be delegated that access by the line owner. Before delegating access to your phone number for another user, review the line's call settings in the Calls tab in Microsoft Teams and decide when you want delegates to receive calls.
Delegates can be simultaneously rang or rang when you are not available. These options will not appear until you have an active delegate:
Receiving calls: When you receive a call. When you have an active delegate, the default will be to also ring your delegates:
When you can't answer a call:
Scroll down to Manage Delegates
Add the user(s) you want to have access and assign them the correct permissions:
Assigned users will also get a chat message from you with their permissions:
Delegate's view:
Delegates will now see a tab with your extension in their Calls settings, if you have given them the "change their call and delegate settings" option, they will be able to assign/unassign other users as delegates for you.
From the same Settings > Calls menu, you can also change the ringtone for calls delegated to you to help identify if the call is coming from your line, or another line:
If given the "Make Calls" option, users will be able to call others and appear as your line.
If you give the "Receive calls" option, your delegate will also receive calls to your line:
If given the "Join active calls" option, delegates will be able to join a call in progress on that line from their Calls tab:
Resource accounts
Once Information Services sets up initial delegate access to resource accounts, Owners can then set additional users to have delegate access.
Voicemail
Individual phone line call delegation does not allow delegated users to see the voicemails of the line they have been delegated. Shared Phone users will need to set up email delegation from the resource account tied to the shared phone number they would like to receive voicemails from.