I have a drop down list with options "yes" or "no". How is it possible to have a prompt on each selection e.g if selected "no" then a meassage appears go to 'enter date field'

You could try to put some code behind your combo box. If you use an If statement and then vbyesNo function that should work ok.

If selection = vbyes & selection then
Msgbox "Go to enter date field"
else
'do nothing
end if
end sub