The operating mode for logical partitions works just like operating mode on a system without logical partitions.
For more information on how operating mode works and why you may need to change it, refer to Operating Mode of an IPL.
To change the operating mode for a partition, you should be working with the remote control panel. You need a Service Tools user ID with operations or administration authority to the System Partitions function in Dedicated Service Tools (DST).
Refer to Change operating modes and IPL types for instructions on how to change the operating mode for a partition.