I don't really go beyond the office manager out of respect for her position, until later and if that happens usually she/he is responsible for taking me that far.
When I do a f/u I do everything humanly possible to do something different each and every time. I am NOT a salesperson and if I try to be one..it backfires on me <g>
I will mainly get the biller or OM talking or I might even talk about something specific like any coding changes, etc. If I get them to talk, usually it turns into them complaining and then I empathize with them and they love that. I don't have a script, I completely wing it, I'm myself and I try to get them to do most of the talking. I also take really good notes!