How to change SAP default client

To change default client for SAP system, I found the following way:
In file explorer: open the instance profile, for example: D:\usr\sap\C11\SYS\profile\C11_DVEBMGS00_win2k3
add login/system_client=800.
Stop and restart the SAP system.

NOTE: directly edit the file is not sugguested by SAP, the correct way to change a parameter is to use Tools->CCMS ->Configuration->Profile Maintenance.

1. RZ10
2. Import the profiles; Utilities->Import profiles->Of active servers
   
3. Extended maintenance the profile; Change
4. Create new parameter or edit existing parameter
5. Save, activate, and restart the server.
   

References:
Some SAP parameters.
How to change SAP default client?