I wouldn't drink a second bottle unless your surgeon directs you to.
Chances are it will work by the end of the day. But even if it doesn't, there is really no reason they should need to cancel your surgery. During this surgery, they don't do anything to your large intestine. So it shouldn't matter if your large intestine is cleaned out or not. That's why many surgeons don't even recommend a bowel prep before RNY.
Kelly
Disclaimer: I am not a doctor and do not play one on TV. I've done a lot of research on vitamins but am not qualified to give medical advice. I'm happy to share my research with you, but you should see a health care professional if you want medical advice.
Check out my blog at: storyofmyservicedog.blogspot.com/