Dual run
Migration checklist
Move a number only when identity, emergency location, and recording have a landing zone. The ladder for a CUCM-to-Webex dual run is on the flow page. This is the checklist around it.
| Phase | Check | Rollback |
|---|---|---|
| Discover | Who owns the number today, which gateway, which recording profile, which emergency location. | Nothing has moved. Write the owner down. |
| Normalize | +E.164 on both systems so the same digits mean the same destination. | Keep the old habit in a translation you can remove. |
| Canary | One user. Inbound, outbound, hold, transfer, voicemail, and emergency callback to the right site. | Send the number back to the original system the same day. |
| Cut | A named cohort, a window, and one person who can stop the window. | The trigger is a failed canary proof, not a feeling. |
| Evidence | A ladder, a CDR or cloud record, and the emergency test you are allowed to run. | If evidence is missing, you are not done, even if users are quiet. |
From platforms other than CUCM
The same five rows apply to a PBX, another UC cloud, or a contact-center number. What changes is the object name: a Webex location, a Teams voice routing policy, a UCCE dialed number, a Webex Contact Center entry point. Do not reuse a CUCM CSS screenshot as if it were the other product's screen.
Florida Crystals, in Microsoft's public story, decommissioned on-premises PBX lines after Teams Phone. That is an outcome on their page, not a template you can copy without the discovery rows above.