Good Morning!

I am wondering how to copy a cell and paste it so that the cell reference
within the formula changes. For example:

=IF('EAST Region PSR Detail '!A9=""," ",'EAST Region PSR Detail '!A9)
when dragged down becomes
=IF('EAST Region PSR Detail '!A10=""," ",'EAST Region PSR Detail '!A10)

What I need to accomplish is to have the cell reference within the formula
to change by 6 integers vs 1, so the correct formula would be
=IF('EAST Region PSR Detail '!A15=""," ",'EAST Region PSR Detail '!A15)