Does anyone know of a formula that will put a value into a blank cell? So far
it seems that all of excels formulas look at values and conditions of a cell.
It seems none put a value into a blank cell.

Background for the question:
I've created a calendar to track vacation time spent in a given year using
excel. Each day of the calendar is made up of 2 cells (one on top of the
other). The top cell for the day contains the date. The bottom cell the user
will enter either a 'V' for vacation or 'S' for sick time.
So far I have the calendar setup so that when I change the year excel will
automatically change the calendar's days and dates to make them accuate for
the given year.
I want to add a piece that will fill the bottom cells with an 'H' for the
company "approved" holidays. I know I could put a formula into all the cells
of the calendar that would check the date against a list of Holidays and fill
the cell with an 'H'. The problem is I need the bottom cells to be blank so
that the users know those cells are for data enty.