Column A is a list of user names that repeat many times. Column B is a list
dates corresponding to the names that repeat in column A. Column D is a list
of Active user names that do not repeat.

I need to look up the Active user name in Column D from Column A in order to
return the greatest/most recent date from column B.

Example of existing data:
User Name Date Active User Name
JohnDoe 03/20/09 JohnDoe
JohnDoe 02/20/09 JaneDoe
JohnDoe 01/20/09 MargeLoe
JohnDoe 12/20/08 DonRoe
JohnDoe 11/20/09 PhilWoe

Example of search results:
User Name Date Active User Name
JohnDoe 03/20/09 JohnDoe