Missing Dates

I have a worksheet with 226749 rows of data extracted from a database. The table has many different Column Titles which includes Name, From Date, To Date, Etc. The issue is that this data is missing dates sometimes.

From Date
To Date

11/01/2012
11/30/2012

10/01/2012
10/31/2012

07/01/2012
07/31/2012

I need a way to find out what names are missing what dates. Any suggestions. Remember there are tons of names, and the table above is already filtered to one of the names. I need to be able to do this without going through every name. Because there are like 40,000. Thank you.