How To Set The Network Owner

Hello,

I want to change my player character during the game but I cannot figure out how to set the network owner manually.
I've seen in the manual that they are using the MsgType.Owner for spawning the player objects at the beginning . But I've no idea how to use it.

I've tried somtihing like this:
Does somebody know how to do this in the new unity networking system?

Thanks a lot!