What is the purpose of the man’s call?

M: Ms. Lee, I’m calling to let you know about the resuIts of the interview you had with us on Monday.(56)I’ve gotten the word from my boss that the position is yours if you’re still interested.
W: Are you kidding? I mean, of course I am still interested.
M: That’s great. When do you think you will be able to start your new position? Is next Monday okay?
W: I’m sorry, but I have not had a chance to inform my current boss about my quitting here, and I think I have to give him two-week’s notice to find a replacement.(57)How about the first of June?(58)