If you trade 1 for 2, you have to drop someone so you don't go over the roster limit. I don't know exactly how many days the commish has set for clearing waivers. Usually 2 or 3.
After the trade clears they go to waivers usually for 2 days until the person highest on the list claims them or they become free agents.
Still not wanting Jones for Gates, Lou?
Long as I remember The rain been coming down. Clouds of Mystery pouring Confusion on the ground. Good men through the ages, Trying to find the sun; And I wonder, Still I wonder, Who'll stop the rain.