What are MR points? Sorry this is my first time using points for travel
MR = Amex Membership Rewards, aka your Amex points.
There are a couple ways to redeem them: 1) transfer to a participating airline, like Cathay, and then book through the airline's rewards program; or 2) book through Amex travel and pay with points.
I would be very wary of option 1), especially with Cathay/Asia Miles (the Cathay rewards program). It may be different now, but several years ago, their rewards ticket availability was absolutely shit, especially in business class. So you could easily end up transferring the points and not find a ticket.
I'd look at option 2, booking through Amex travel with points. Be creative and search one way fares each way separately, varying dates, etc. I've found some killer deals with one way tickets, last year I found a biz class ticket for 200k points, and then just paid cash for the return leg on another airline.