Sometimes you can book a Cathay flight to or from the Philippines using a Philippine Airlines codeshare and save a considerable amount compared to if you book the same flight under its Cathay flight number.
Before doing this, there are a couple of points you may wish to consider. First, as your ticket is not booked using a One World flight number, you will be unable to rely on Marco Polo Club or other One World programme status to use a lounge. Secondly, you will not be able to credit the flight to Marco Polo. Dependent on the fare class, you can credit either to Philippine Airlines’ Mabuhay Miles programme, or ANA or Etihad’s programme, if you are a member.
Apart from that, the flight is still a Cathay flight and booking as a Philippines codeshare may in some cases represent a significant cost saving.