Administrative trainee covering rent by son accepts new tenancy (7)

I believe the answer is:

attorns

I'm a little stuck... Click here to teach me more about this clue!

'administrative trainee covering rent' is the definition.
I can't judge whether this definition defines the answer.

'by son accepts new tenancy' is the wordplay.
'by' becomes 'at'.
'son' becomes 's' (genealogical abbreviation for son).
'accepts' means one lot of letters goes inside another.
'new tenancy' becomes 'torn' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'at'+'s'='ats'
'ats' placed around 'torn' is 'ATTORNS'.

Can you help me to learn more?

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.