Presence is force of personality, raw leadership and impressiveness. It's used for things like giving speeches to large groups. Politicians tend to have high Presence. In social combat, Presence is like Endurance, representing how much of a beating you can take.
Rapport is being charming and likable, personally. It's used to persuade people to do things one on one. Salesman and seducers have high Rapport. In social combat, Rapport is like Athletics representing how easily you can avoid or laugh off the social attacks of others.
For example, I'm not very impressive looking, and tend to be kind of quiet. But people who get to know me, like me, and I can persuade people to do things for me very well indeed. I clearly have a higher Rapport than Presence.
