Return Work Permit ?

My aunt was denied for form I-485, and in the letter was told to return her work permit and send it through the mail. one of the lawyer that she went to informed her she doesn’t have to send it, that she can still use it because on the ID it has an expiration date. Is that correct? I don’t want her to get in trouble if she doesn’t send it and just want to know if the lawyer is correct. Thank you.