First, list the one or two things (talking points) you remember about the person and the event so you can re-establish rapport.
Second, send them a short note and reference meeting them and an interesting point about the event. Make a general statement about having breakfast or lunch together soon.
Third, make the call–keep it conversational and consider these points:

A) Build Rapport–Refer to the previous event. Recall from your notes your talking points with them. (Note: focus on the person not your product line. Your goal here is to increase their comfort level, not to make this a one-call close).
B) Express a desire to meet with them again for breakfast or lunch or a game of golf, so you can find out more about their (business or practice, interests in charitable activities, sports interest and involvement, etc.).
C) Then suggest two congruent potential timeframes, i.e., “Would Monday morning or Tuesday morning be best for you?
D) If there is hesitation, your enthusiasm often will open the door. Suggest a place to meet by simply saying you know a great new spot for breakfast/lunch________. Have you been there? Then re-suggest the date and time.
Remember, the objective is to make them comfortable by building rapport through a conversational tone and then create willingness for them to have breakfast/lunch with you.