I have known a MBB junior partner for around a year. He is an alumni and we have scheduled a call once and hangout for coffee once. Except these two events, I haven't contacted him for more than 6 months. Given that he has some personal understandings about me, I am thinking of approaching him directly and seek his help for referral. Is this move suggested, and how can I frame the request in an elegant and polite way, as we are not acquaintance? Appreciate your thoughts.