I have the following IF Statement

=IF(O30<1000,"Have a Great Day!","Please pay Promptly")

Basically if cell O30 is less than $1000 the result will be Have a Great
Day; otherwise it will be "Please pay Promptly".

I would like to also add an option for if the cell is Blank that there be
nothing in the end result.

Currently it is always saying "Have a Great Day!"

Thanks in advance.