Does anyone know how to schedule an automatic change based on real time date
and time.

Example:

I have a rate sheet for which I have to make changes all the time, I am told
30 days in advance of the changes that have to be made. What I want to do is
find out a way I can make the changes to certain cells today and schedule
them to take effect at a later date automatically. Is this even possible?
--
Jheison