Hi all,
Could anybody help me to complete the last part of the following code (the
one written as capital):

=IF(OR(E:E="PETER",E:E="Ramzy",E:E="Michael",E:E=" Mona",E:E="Marianne")*AND(N:N<"Ok"),NOW(),NO CHANGE IN THE VALUE)

I need some help to do the following:
=IF(B:B<NULL VALUE,"Ok",NULL VALUE)