What it says on the tin. With any POD starting after 24 October 1945, maintain the United Nations as an effective international peacekeeping, promoting human rights, etc. Essentially, how it was in the 1950's and early 60's, where it intervened in Korea, the Congo, and at least partially diffused the Cuban Missile Crisis. Feel free to change the very organization of the institution itself, so long as there is an organization called the "United Nations" that has as its mission statement the same one that ostensibly guides OTL's UN, it's fine.
If at all possible, keep the polchat out of it. The UN can occasionally be a sensitive topic, let's keep the weirdness to a minimum.