I am needing some help with how best to summarize and chart some raw data. I
extracted from an application we use that tracks appointments and dumped it
into excel. The columns I am interested in a
date
name
appt_start
appt_end

Each name is associated with 4-5 appointments for one date.
I am trying to see how much time is between appointments
An example of the data:

12/01/2004 Smith appt_start appt_end
12/01/2004 Smith appt_start appt_end

12/01/2004 Jones appt_start appt_end
12/01/2004 Jones appt_start appt_end

and so on. There can be up to 20 different names each with up to 4+
appointments for each day. The report covers a 3 month time frame so there is
lots of raw data, exactly 8300 rows.
I have sorted it 2 ways:
1. date/name/appt_start
2. name/date/appt_start

I thought I could put a formula in the next empty column to show the time
from the next appt_start - appt_end from the previous line. This of course
would not be in the first appointment of the day or the last.
What I am struggling with is how to best summarize all this and chart. Maybe
I can't, maybe it is best represented in raw form, but any ideas are truly
appreciated!