Can MR points be used to purchase United AL tickets to London: Please advise what is required. Thank you.
The best way to do this, is to use a travel package where you get hotel nights and the amount of miles that you choose. They don't have to be used at the same time.
Here's the most straightforward place to accomplish that: https://www.marriottrewardsairandcar.com/travel/arc.cfm?tab=a