Welcome, @helpkathy. I encourage you to join the discussion here where you'll meet others on dialysis and some who, for various reasons, are not able to get a kidney transplant:
- Dialysis - Stories and Questions https://connect.mayoclinic.org/discussion/dialysis-stories-and-questions/

If your sister would like to get a second opinion at Mayo Clinic, she can request an appointment here: http://mayocl.in/1mtmR63

Go to another clinic. You can register as many clinics as you feel comfortable doing so . You just have to be willing to travel to whatever place you choose every week after the transplant. You can register in as many places, in as many states as you are ready and able after transplant to attend weekly and monthly doctors and lab appointments. You could probably do your lab appointments remotely.

There are certain criteria for an individual to be a candidate for a transplant, they run alot of test on them to determine their decision some are examples such as: they check her heart to see if it's strong enough to withstand the surgery, it could be a number of things, if she smoked or still had nicotine still in system the arteries will not cooperate when attaching a new kidney, could be multiple reasons why they told her that she is not a candidate, were they able to provide you any information as to why? They are obligated to inform her at least why she's not able too and would think there would be some paperwork to say as well. Contact them to try and find out but good luck HIPPA prevents us from knowing anything without patient giving consent which is usually done in person or by signing a release of medical information on her. Let me know what you were able to find out.