Did you overfill them and then drive for a bit...or did you pull pressure out right after the light went off? The way it is supposed to work is this: The light comes on when any 1 of the tires drops 20% below recommended pressure (32psi). When sufficient pressure is added to make up for the loss, the light is *supposed* to go out as soon as the vehicle's speed exceeds 20 mph. I can tell you from personal experience, the light does not always go out like it's supposed to.
Anyway, the last time I had the light come on, I literally drove it to the gas station...filled each tire to 40psi. Then I drove it for the 2-3 couple days. Finally, the light went out. The next morning, knowing that the tires had sat all night and were cold, I decreased pressure in all the tires - until each was just above 32. The light hasn't been on since.
To my knowledge, there is no other way to "manually" reset the indicator. I'd bet there's a way to reset it with a scan tool. If your light refuses to go out, on a more permanent basis and / or if the TPMS light comes on...might be time for a trip to the dealer.