Use date modified to change format & create filter to track change
 

I have a spread sheet of which three columns contain 2006 medical insurance
election information and three susequent columns will contain 2007 medical
insurance election information. (Plan code, tier level & premium) If a
participant does not make a change during the open enrollment period, their
record remains the same, however if a change is made during the open
enrollment period, it must be reported to the carrier. Therefore I have
pre-populated these columns with the default values equal to the 2006
election information. I would like to know if there is a way to

1.) change the format of cells that are modified in the 2007 columns during
the open enrollment period
2.) create a "x" in another column that can be used to filter only the
changed records so they can be sent to the carrier with the change
information.

Thank you in advance for your help.