how do you claim to be an experience RC person if you cannot change a arms??
ok. see the silver bars running down the arms? those are pushrods. remove the screw at the end by the hub. See the other silver bar behind the arms? those are turnbuckles. remove that as well. see the hubs? (kind of wing shaped with some blue things on the side) they have a special dust cap in there, and then a hex head is needed to remove the pivot ball. The dust cap uses a special tool that came with the revo.
once you get everything off that end, then you move to the center. you see those 4 silver nubs on the center black and blue part that kinda looks like this

? those are the pivot pins. pull those out, and the a arms should come loose.
Installation is reverse.