You have on SetACL website manual,besides you can get all switcher options if you type:
setacl -help
straight to your question:
setacl -on "<exactly path to file>" -ot file -actn setowner -ownr "n:Administrators"
setacl -on "<exactly path to file>" -ot file -actn ace -ace "n:Administrators;p:full"
If you are already owner of file of course you can ignore first command.
I surmise from the context of question you have trouble with changing permissions on any file...Well it may happen.Not all work according to theory.Maybe some file is busy and you have to try in safe mode or even in safe mode with command prompt,from System account (example from forum:
Denied Access to D:\ drive )
If owner of any object is TrustedInstaller and you can't change permission in any way according to theory prediction it will be great problem,it may be caused by also WIL restriction
chml: a tool to control Windows Integrity Levels
Unfortunately I can't also find Holy Grail to rule & control all permissions
....