Knitting row gauge - help

[teachermom]

I'm trying to figure out how to adjust row gauge. I'm knitting a sweater and have the stitches per inch fine, just can't get my rows per inch correct. If I change needles, then my stitches per inch are off. I have less rows per inch then the pattern calls for, so I've had to cut out several repeats of the pattern stitch - which doesn't look bad and no one but myself will know, but I want to know if there is a way to fix rows per inch and get that gauge correct.

Thanks