Altering a finished project?

A while back, I knitted my daughter a simple beanie-type hat–stockinette with about a 1" ribbing around the brim (nothing fancy). Anyway, she just got a ear infection in both ears, and I started wondering if perhaps adding on some earflaps might be a good idea to prevent future ear infections. The hat looks very similar to this pattern.

Can I pick up stitches around the area where the earflaps should be and knit that way? I’m wondering how it will look since the brim is ribbed (yarn is 100% worsted weight merino wool).

I suppose I could knit another hat…but…I was hoping not to, and, if I just add on to the hat she already has, it will be ready for her to wear much faster than making a completely new one.

You could pick up like you said and then make the earflaps in ribbing, too…sounds like it would be cute!