In order to make it bigger or smaller you would have to adjust it all the way around. The difference in pattern sizes is only 1/4 to 1/2 in on all sewn sides. If you would need to make this particular dress bigger you would add on to each side of the bodice and to the fold and bottom of the skirt(in order for the skirt to be long enough). Measuring your dog and hold the pattern that you make to your dog to get the best fit. Good Luck, I have a hard time putting what I mean into words, it is just easier for me to show someone.
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Jennifer, Proud mom to Micah

, Candy

, Nikki

, Gizmo

, and Crickett (gone but NEVER forgotten)