1. Remove Skype server from topology
2. Publish topology.
3. Run Skype Server Deployment Wizard local setup on server to remove Skype components
4. Uninstall SQL Server. Front-ends have SkypeLocal and RTCLocal instances. Remove both, rebooting between instance removal. Edge only has RTCLocal instance.
5. Remove SQL Server 2012 Management Objects (x64)
6. Remove SQL Server 2012 Native Client (x64)
7. Remove Microsoft System CLR Types for SQL Server 2012 (x64)
8. Remove Microsoft Skype Server 2015, Front End Server
9. Remove Microsoft Skype Server 2015, Core Components
10. Delete C:\Program Files\Microsoft SQL Server
11. Delete C:\Program Files\Microsoft Skype Server
12. Delete C:\CSData
13. Rename server and restart
14. Wait until AD replication completes with new server name.
15. Open Topology Builder, add new server to existing pool and publish.
16. Reinstall Skype components and all cumulative updates
17. Generate new certificate with updated server name and assign to appropriate services using Skype Server Deployment Wizard.
18. Restart all servers in pool at same time (only relevant for front-end servers in an Enterprise pool).