I'm making a rectangular flat hat for my husband, but misread the pattern and have been doing 30 stitches per row instead of 40. I tend to knit rather tightly, so there's less stretch than usual and ten stitches can really make a difference. If I just kept going and got all of the rows done and cast off, would it be possible to turn it sideways and add rows in that direction to make it wider? Or do I basically just have to restart the whole project?