First you need to check some information for your system on the HMC. Issue the command vtmenu to get the managed system ID and the names of the partitions

hscroot@localhost:~> vtmenu

Retrieving name of managed system(s) . . . 108F19C

———————————————————-
Partitions On Managed System: 108F19C
———————————————————-
1) MANUFACTURING Running:
2) RETAIL Running:

Enter Number of Running Partition (q to quit): q

Bye.

On this example I tried to soft reset the partition called MANUFACTURING

hscroot@localhost:~> chsysstate -m 108F19C -r lpar -n MANUFACTURING -o reset

Since it didn’t work out as expected, I decided to power off the LPAR

hscroot@localhost:~> chsysstate -m 108F19C -r lpar -n MANUFACTURING -o off

hscroot@localhost:~> vtmenu

Retrieving name of managed system(s) . . . 108F19C

———————————————————-
Partitions On Managed System: 108F19C
———————————————————-
1) MANUFACTURING Ready:
2) RETAIL Running:

Enter Number of Running Partition (q to quit): q

Bye.

I turned the partition on and after that it worked flawlessly

hscroot@localhost:~> chsysstate -r lpar -m 108F19C -o on -n MANUFACTURING

hscroot@localhost:~> vtmenu

Retrieving name of managed system(s) . . . 108F19C

———————————————————-
Partitions On Managed System: 108F19C
———————————————————-
1) MANUFACTURING Starting:
2) RETAIL Running:

Enter Number of Running Partition (q to quit): q

Bye.