What it does

The boss/admin feature. A delegator (the manager) lets one or more delegates make and answer calls on their behalf, and the delegates see the manager's line, its active calls and the manager's status in their own client. Microsoft calls it shared line appearance; most of your clients will call it "what the PA had on the old Cisco".

Key facts

• Both the delegator and the delegate need a Teams Phone licence. The manager needs PSTN connectivity and a phone number to receive external calls.
• A delegate without their own number still has to be Enterprise Voice enabled: Set-CsPhoneNumberAssignment -Identity <user> -EnterpriseVoiceEnabled $true.
• Teams Only mode is required — it doesn't work for users still in Skype for Business coexistence.
• Delegation is allowed by the calling policy setting Delegation for inbound and outbound calls (AllowDelegation), which is on by default.
• Three permissions per delegate: MakeCalls, ReceiveCalls and ManageSettings. Admins manage them with New-CsUserCallingDelegate, Set-CsUserCallingDelegate and Remove-CsUserCallingDelegate (Teams PowerShell module 4.0+).
• Microsoft recommends no more than 25 delegation relationships per user. The service allows more, but the UI degrades past that.
• Circular delegation (A delegates to B, B delegates to A) is only permitted on Teams phone devices.
• Feature support varies by client: joining an active call on the manager's line works on Windows desktop, web and Teams phones but not on Mac or mobile; shared call history is desktop and web only; hold/resume isn't on mobile.
• To ring delegates alongside the manager, set the manager's forwarding to simultaneous with -ForwardingType Simultaneous -ForwardingTargetType MyDelegates on Set-CsUserCallingSettings.
• When a delegate places a call on the manager's behalf, the manager's number is presented — so the PSTN provider has to accept that caller ID, including from a different geographic location.

When to use / skip

Use it for exec/PA pairs and the small number of people whose line genuinely needs a second pair of hands. It's the closest Teams gets to the bridged line appearance people remember from desk-phone PBXs, and on a Teams phone it's quite usable.

Skip it when what you're really building is a team answering a shared number. Five people "covering" a department line through delegation is a call queue or a shared calling setup in disguise, and you'll lose reporting and queueing behaviour. Likewise, if the requirement is just "someone else answers my phone when I'm off sick", a forward or a call group is simpler and doesn't give the colleague the ability to call out as you.

The device question matters more than the licence question. A PA who works mainly on a Mac or a mobile gets a noticeably cut-down experience — no barge into the manager's active call, no shared history. If the PA lives on a desk phone, check the specific model and firmware supports the delegate view before promising it.

Configuration decisions

• Which permissions each delegate gets. ManageSettings lets the delegate change the manager's forwarding — fine for a trusted PA, less fine for a rota of temps.
• Ring behaviour: delegates ring simultaneously with the manager, ring only after a delay, or the manager forwards immediately to delegates so the PA screens everything.
• Whether delegation is configured by users themselves or centrally via PowerShell. Central control is better at go-live and for audit; self-service is better long term.
• What device the delegate uses as their primary interface for the manager's line.
• Whether the manager's line carries a caller ID that every delegate location can legitimately present on the PSTN.
• Matching calling policies across the manager and all their delegates.

Gotchas

• Mismatched calling policies are the most common cause of "the PA can't forward the boss's calls". The delegate operates under their own policy, not the manager's.
• Unanswered calls go to voicemail after 30 seconds by default (per the Learn article) unless changed — managers sometimes expect delegate ringing to extend that window and are surprised when calls go to voicemail before the PA picks up.
• Delegates calling out as the manager from another country or region can be rejected or rewritten by the carrier. On Direct Routing, look at what your SBC and carrier do with foreign caller ID before go-live.
• The 25-relationship guidance is about UI usability, not a hard block, so nobody warns you when you've gone too far — it just gets slow and messy.
• Delegation needs Teams Only mode, so any users left in a coexistence mode in a hybrid estate quietly miss out. Clean up coexistence first.

Consultant notes

• Build a delegation inventory during discovery: who covers whom, with which permissions, on which device. Then script it with New-CsUserCallingDelegate for go-live day rather than walking each PA through the client.
• Demo the delegate experience on the actual device the PA will use, before migration. Feature gaps on Mac and mobile are the usual surprise.
• Pair delegation with a deliberate forwarding rule on the manager — simultaneous to delegates is the default most PAs expect.
• Keep the delegate and manager on the same calling policy; build it into your group-based assignment so it doesn't drift.

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Revisit the client capability table next time the Mac and mobile clients get a calling refresh — the gaps there are the main reason PAs push back