This small article describes how to change the ct_node_id in case two LPARs have the same.
1. Duplicate Node ID after LPAR Cloning
When you clone an LPAR by splitting up a copy of the rootvg of an existing LPAR on storage level, both the original and the cloned rootvg have the same /etc/ct_node_id. This confuses the HMC and communication between LPAR and HMC will only partly work. DLPAR for instance doesn’t work if two LPARs have the same node ID in /etc/ct_node_id.