Protecting worksheet

[Kimti]

Hi,
I have a sheet with some protected cell, which allows others to enters some
date on the unlocked cells. I would like to see those unlocked cells to be
locked as soon as some one enters the date and saves the file.

 

[Kimti]

There was one mistake in my questions. Please read data instead of date.
I mean to say that if any one enters a data in a blank unlocked cell and
save the file, that cell has to be locked.