1.
If someone signs off, they write a final message at the end of a letter or they say a final message at the end of a telephone conversation. You can say that people such as entertainers ~ when they finish a broadcast.
O.K. I’ll ~. We’ll talk at the beginning of the week...
PHRASAL VERB: V P
2.
When someone who has been unemployed signs off, they officially inform the authorities that they have found a job, so that they no longer receive money from the government. (BRIT)
If you work without signing off the dole you are breaking the law.
PHRASAL VERB: V P n (not pron), also V P