I have earned airline miles on American Airlines and Quantas Airlines (both members of One World) and want to use the miles to purchase a ticket on LAN Airlines to Peru.

How does this work? What is the best way to get the most miles credited to me?

I am a frequent flyer member of all three airlines and have approx. 12,500 miles on American, 15,000 on Quantas and 5,000 on LAN.

Thanks!!!