Hi Natasha,
For changing the work status, log on to EPM Ofice Add-in Excel, create an Input Schedule containing entity data, select the option "Change Work Status" under Save Data and provide the required information there. When you change the work status to say, LOCKED and then try to enter and save data in the input schedule you will receive a message that you cannot save data.
You don't need to create Manager property. Owner of a node level entity automatically becomes manager of all base entities under it.
Hope this helps.
Regards,
Ramu