Press and release the SAT button on the top left corner of your remote control--buton will briefly light up.
Press the up/down buttons on the front panel of the DISH receiver (some may be inside front panel door) to see if the receiver changes channels.
If the issue is only on ONE receiver, unplug the DISH receiver for 10 seconds and plug back in.
Please note: It may take up to 5 minutes for the reset process to be completed.