Sorry, but PR Mabuhay Miles has no airline partners at all. If you make a few trips you can use your miles upgrades, but that's about the only thing to use them for except award tickets on PR.

You mention that your company books your tickets, but if you can infuence the buyer at all then NW normally competes on prices from the LAX/SFO/SEA to Manila with Philippine Airlines. The NW prices are usually nearly identical if availabilty exists in the matching fare classes. It would involve a stop in NRT but well worth it.

I don't care much for PR, but for domesic flights in the Philippines its a lot better than Cebu Pacific as PR at least has a business class on domestic flights.

BTW: If this is your first time in Manila, make sure you have a printed copy of your itinerary with you when you go to the airport in Manila or they won't allow you to enter the terminal building.