staff rota with holiday

Hi I've attached a staff rota which i created in Excel.

it works well, but i want to take it a step further and include holiday booked.

I'm going to create a second sheet with all dates and people's names (currently A, B, C ...)

eg.
A B C D
13/08/10
14/08/10 x x
15/08/10 x

I want to place an X in the cell whens someone books holiday.

I then want the rota formula to be cross reference the holiday booked sheet
with the date and person on the rota pattern

If the holiday booked sheet has an X in the cell which matches the person's name and date, then the text in the cell will change. ie. "DAY" changes to "LEAVE"

I'm assuming i'll need to use Vlookup and Hlookup along with an IF statement in the the same formula.

Any advice or help would be much appreciated

Thank you