Issue with WNDR4500v3: Intermittent WiFi Connection

Thanks for the welcome and reply! The firmware installed is the current version 1.0.0.32. There are no other wireless devices near the router. It is on top of my desk hutch near my PC. There are 3 to 4 wireless phones (only 1 during the day), an additional computer on a home network, and a Nintendo Wii (which is barely used).The phones and my son's PC lose connection, but it's not as bad as it was before I reset my router. All devices at night have faded in and out of connectivity, but only for a few seconds at a time. I haven't tried coming closer to the router when I've lost connection, but I'm in an adjoing room where the router is located (with 15 feet). I use both channels according to how I need to use it (distance or speed). I didn't encounter this issue until several weeks ago. How do I change channels on the router? I'm willing to try anything! Thanks again for the assist!