From time to time you may need to give up a Dial in conferencing number and assign a new one for whatever reason. This is a quick how to on the subject.
Fist you should get the conference bridge identity.
Get-CsOnlineDialInConferencingBridge and note down bridge identity
Then you can run something similar to this:
Set-CsOnlineDialInConferencingUserDefaultNumber -FromNumber 14255550100 -ToNumber 14255550101 -NumberType Toll -RescheduleMeetings -BridgeId 9884626f-dcfb-49f4-8025-912f5bc68fdc
The above cmdlet simply replaces the default number from 0100 to 0101
Once that is done it will start the process of rescheduling meetings.
Now we can move forward with unassigning the number from a conference bridge and release it.
The cmdlet we want to use is:
Unregister-CsOnlineDialInConferencingServiceNumber -BridgeName “Conference Bridge” -RemoveDefaultServiceNumber 14255550100
Once I ran the above cmdlet it turned my service number to “unassigned” which then I was able to release the number.
The simplest way to do this is to go into your Teams admin portal. Then select voice –> phone numbers –> select the phone number and then click release.