I had a bit of a hard time find this doc on MOL so I thought I'd paste it here.
Feel free to add your experience.
Ralph
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Knowledge Base Article   
Article ID #
11-5163-00014  Article Type
How-To Guide 
   
Article Title
How to remove a Controller from an existing Cluster  Publish Date
Jan-10-2012 
Description/Symptoms  
How to remove A network element from a cluster 
 
Body/Solutions  
If you are going to remove a controller from a sds network you cannot just power down and remove controller.
You must leave controller running and delete all extensions and have them sync to all other controllers in network . Then delete the switch out of cluster and delete network element
Details can be found in the online 3300 help under: SDS - Removing a Data-Sharing Element  
 
Test Result  
 
 
Article Search Keywords  
SDS, remove, element 
Product(s)   Product Release(s)  
3300 Integrated Communications Platform (ICP)  4.0; 4.1; MCD 4.0; MCD 5.0 
   
Product Family   Operational Task  
Integrated Communications Platform  Maintaining/Upgrading; Programming