Asking for a referral works best if you specify the type of person that you hope to be referred to, AND you match your request to fit the person you are asking. Three examples:
 
1. If I'm speaking to a Sales Manager at a large company: "Can you think of 2 or 3 other sales managers in your firm that might also benefit from Negotiation Skills training for their sales team?"
 
2. If I'm speaking to a higher level sales executive (VP of Sales, for example) and I find out that the VP is responsible for another group that could benefit from a training workshop: "Would you be willing to refer me to a few of your distributors? It would be a win/win if we could teach their salespeople the same skills that your direct salespeople are learning."
 
3. If I'm speaking to an HR Manager who is well-networked: "Would you be able to give me the names of a couple other HR managers at other companies who would be interested in the type of training that we provide?" 

If you would like some assistance on how to ask for and use referrals, we can help.  We'd like to hear your ideas on how you go about asking for referrals.