You can if you know what you're doing, but I don't think it's all that simple. You might be able to just make a larger size and make it work. I'm not sure though.
This one is for a basic vest, but it does give you info for resizing it to fit various sizes so maybe that would work.
http://mindofwinter.prettyposies.com/pdfs/DadVest.pdf
Here's a pattern for DK weight yarn (yours) that might work.
http://fablehandknit.com/patterns/gilmore_vest.htm