I may have to travel for work next month, from LAX to AUH. Work will only pay for a fully refundable econ (S) fare (I know!). What's the best way to upgrade to Business? The big restriction is the flight must be booked on a US carrier, although a code share is fine (ie booking a VS flight via Delta). Route is not important, although a few days layover in London are ideal. What's the best airline/route that can be booked via a US carrier codeshare and upgraded to Business with the least amount of miles? Premium Econ also an option. I have plenty of Virgin and Amex miles for this.