Get it changed over by immigration office to the new passport, especially if they poke a hole in the top of the old passport to make it invalid and change the passport numbers in the system, when I got a new passport last year the American embassy gave me a paper to take to immigration with me and they just gave the same visa in the new passport
yes I understand that but coming into the land border at Cambodia twice already in a short amount of time the chances of being turned away are just as likely if you look at previous post it’s recommended by many people not to do so and having just been there myself at the beginning of this month and seeing one person be turned away I’m just sharing my thoughts