Need to insert stripe into a striped scarf

I am knitting red, white, and blue scarf with wide horizontal stripes in a complicated bumpy rib pattern. Each stripe is 24 stitches in 16 rows. I accidentally skipped one of the white stripes, and I don’t want to un-knit what I’ve done. Is there a way to separate the blue stripe from the red stripe, knit the white stripe, and then reattach the blue stripe onto the white stripe?

I have not woven in the tails yet, so there’s a loose slip knot and a few inches of yarn at the beginning/end of each stripe. The first row of the pattern is P2 K2 to end. The last row of the pattern is K1 P1 to end.
:doh: Thanks!

Welcome to KH!
Yes, you can do this. It involves a procedure like this:

You don’t have to cut the yarn however. Undo the yarn strand coming from the color closest to the cast on. You’ll have to pick it out stitch by stitch from the next color. As you do, live stitches will be freed up and they should go on a needle to hold them as you unpick. The next color will also show you loops and they can go on another needle or a stitch holder. These loops are actually the loops between sts so you’ll be one stitch short (23sts) but you can compensate for that when you join with the newly knit white stripe.
Maybe give this a try on a test swatch first to see how it goes.
This video is nice too because it shows picking up the sts first.