Remember to be sincere yourself when you talk to him/her.
No matter what he or she says to you, send him/her a Thank You note for his/her time. Even he/she rejects you. Because now you don't have to waste your time to worry about whether or not he/she will help you. You can save your energy to work out something else. You never know. He/she may regret what happened before and may want to do something kind to save his/her own conscience. Like said, You got nothing to loose as long as you have no-evil intention from your side.Good luck!!
