I am creating a spreadsheet to keep track of vacation time. I would
like to have a drop down list that employees could select there names
from and on any given work day. I would like to have a means of
making sure that employees can only select or remove themselves from
any day they select to take off hence the need to protect or validate
who is trying to make a change to what. There can only be 2 employees
off any given day per shift.