Meaning: End a message
Example: I'll SIGN OFF now, but will write again next week.
Meaning: Close a claim for unemployment benefit
Example: I SIGNED OFF when I got my new job.
Meaning: Stop doing something to leave
Example: I'm SIGNING OFF now and going home- I'm shattered.
Meaning: Give someone a letter to be away from work
Example: My doctor SIGNED me OFF for a month with back problems.