Are there ways to shift a breech baby before birth?

Yes. There is a procedure called an external cephalic version to rotate a breech or transverse (sideways) baby to the correct position which is head down. The doctor or cnm uses his or her hands to apply pressure on the abdomen allowing the baby to rotate. This procedure can be uncomfortable for the mom and requires an experienced provider to be done safely.
Moxibustion. I wanted to add a traditional chinese medicine option to the excellent ideas provided by dr. Collins & dr. Livingston. Moxibustion (heated mugworth)is applied to major acupuncture points to assist the baby in moving from a breech position to a head down position. This site explains: http://www.Pregnancy.Com.Au/birth-choices/breech-birth/moxibustion-for-breech-presentation.Shtml.
Sometimes. Your question is better to refer to your primary ob/gyn doctor, who will provide you with detailed response. It's out of my specialty field, sorry.