Exposing corals to air?

[Gools]

Is it OK to expose your corals to the air? I want to do a water change but after draining a couple of gallons some of my corals are being exposed to the air. And I don't want to move them all down. The corals that would be exposed are, Horn Coral, Montipora dig, acro, and umbrella coral. I know that in the wild acro's are above the water at points in the day, and that there slime coat protects them but what about the other? I would only need about 5-10 minutes total time left in the air. Thanks