The bottom of the piece requires a K2,P2 rib. Would I be able to knit that back on?

I'm working on this sweater from Lion Brand:
http://cache.lionbrand.com/patterns/70112.html?noImages=0
I wanted the sweater a little longer, but have now ended up with something closer to a tunic. The rows I added are all at the bottom of the back of the sweater and this sweater is knit from the bottom up.
Can I get rid of some rows without undoing the whole back?
Any help would be appreciated.

I love the detail in your cardigan. It looks perfect for those cool summer evenings.

Thanks so much! I will try these ideas and hope for the best.

Apparently I am spaghetti strap impared. 
I have a dress that I am currently working on that calls for thin straps that you sew wrong side out and then turn right side out using a needle and thread. The picture shows the needle passing through the tube and the fabric turning with it.
I've been trying to do this for days but it just will not work. Is there any other tip or trick that might help me turn the strap/tube?
Also, It is very thin- only about 1/4 of an inch wide.
Thanks!

Love the pattern on the bag, very interesting to look at. Also, those handles look great.

Love the colors! That turtle is very cute.

Can I just say- Amazing! I love the colors, along with the pattern they really keep the eye interested in viewing the whole blanket. Such great detail. Wonderful job.

I love the scarf! Red is my favorite scarf color this winter.

I am on a mission to make this scarf look good. I will try your pattern variation. I think it is just the answer I was looking for, thanks!