Do you mean that you want to uninstall Skype for Business server 2015 production environment?
If so, you can follow the steps as below:
- Step 1: Disable Lync users in the pool
- Step 2: Remove the configured conferences in the pool
- Step 3: Remove authorized applications to communicate with the pool.
- Step 4: Remove the votes attached to the pool configurations
- Step 5: Delete the voice components attached to the pool
- Step 6: Remove the EDGE server
- Step 7: Remove the environment
- Step 8: Remove the database
- Step 9: Reverse Domain Preparation
- Step 10: Invert the preparation of the forest
For more details, please refer to Step-By-Step: Uninstalling A Microsoft Lync Server 2013 | Microsoft Learn. It is also applied to Skype for Business server 2015.
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