You'll have to use a material with a smaller count per inch. Instead of 14 count, try 11. I don't have a calculator handy but if you do, divide the number of stitches (both vertically & horizontally) by 11. That will show you the finished size.
: I have a pattern that is 5 by 7 finished size
: on 14 count. How can I stitch it so that it
: comes out to be 8 by 10, or 10 by 14?