Is it possible? Can you frog brioche? Of course. It’s getting it back on the needle that’s tricky. I’m here to help! I’ve had a lot of experience frogging…(for newbies: frogging means rip-it, rip-it, rip-it).
You can rip one row/round at a time, alternating colors, but it’s just as easy to rip them simultaneously. The trick is to rip until you’re close to where you want to end up, and then tink (un-knit, knit spelled backwards) the last row or round, one stitch at a time, picking up each stitch as it’s freed from the yarn. This is also how I frog regular knitting.
After I made this video, I frogged this project completely, because it’s a little too big. But I wanted to show you how it worked, before completely undoing it. It turned out to be just a big swatch!
PDXKnitterati 
Oh, mate ! – you are talking my language ! 😦
The amount of frogging I’ve had to do when learning how to knit brioche would stuff a very large duvet/doona or two.
But the satisfaction obtained from doing it and finding that it’s all hunky-dory and can then be progressed ! – no describing.
I’m very happy that Ravelry has a little lead story on Cat’s leaving us. There can’t be too much copy written on the person she was.