My daughter turned from breech to vertex at 39wks...she was born 10days later weighing 12lbs.
I would suggest NOT scheduling a c-section and waiting for labor to start. Babies CAN AND DO turn VERY VERY late in pregnancy, and even during labor.
She can do a tilt board (ironing board or other wideish bench thing) lean one end on the bed or couch or a chair, and secure the other end on the floor(wedged against a wall works) head at the bottom feet at the top. 20min 3x's a day.
She can try accupuncture
She can try 30C Pulsatilla 3x's a day (homeopathic med...will not hurt the baby or her at all, but there is some evidence that it encourages baby to move and turn)
Swimming can help take the weight off so baby can turn eiasier
She can also schedule a Version...If I were her I would schedule one EARLY like 35-36wks...most Docs don't like to do them until 38wks, but it's more likely to be successful earlier rather than later...and if baby turns back there is still time to do another version.