If problems

I have had a ton of help here today so thanks to all.
this is my last issue.

three columns
"D" Order Date...date invoice was entered
"E" Measure date...date measure was actually done
"F" Anticipated measure date...Date 14 days after "A"

If "E" when entered is past the date in "F" I need for nothing to happen.
if "E" when entered is within the 14 day period i need "F" to show nothing

In F currently is the following:
=if(d4=0,"",d4+14) date in F stays no matter what

I tried in F the following:
=if(E4>D4,D4+14,D4)
although the above works how do I make the date clear if the date is before that entered in E?
Thanks

I'm not quite sure I follow. What should happen if E4=D4?

A date can be less than, equal to or greater than another date.

Some possibilities

=if(E4>=D4,D4+14,"")

=if(e4>d4,d4+14,if(e4=d4,d4,""))

=if(D4=0,"",D4+14) in column F
this works like i want it to giving me the automatic 14 days out. When i enter a date into column e i need the date in column f to disappear if the date entered is before that in f?

sheesh, can you upload a workbook? that would be so much easier to understand.