How do I change my AT&T wifi router channel?

You may experience weak or dropped signals if say a cordless phone and Wi-Fi gateway share the same frequency channel or if two gateways sharing the same frequency channel are located relatively close to each other.

A potential fix for this issue is to change the channel, thereby reducing frequency interference. The steps below show how to check which channel you're currently on and which channels are available for you. Trial and error testing may be required to find the right channel for you.

1. First you will need to gather some information in order to access and make changes to your router. You can locate the information needed on the sticker on the side of the modem. You will need the following info. Device Access Code and the IP address listed under For Advanced Device Configuration (should look like 192.168.1.254).
   
   
   
2. Open a browser (such as Internet Explorer, Firefox, Chrome or Safari) and in the address bar, type http://192.168.1.254
   
   
   
3. Select Wireless.
   
4. Scroll down to Network > Wireless Channel. From here, you can change the wireless channel. You want to pick the one with the least amount of interference. It may take some trial an error to determine an optimal connection.
   
   
   
5. After you have selected the appropriate channel please ensure to click the Save button at the bottom of the screen.
   
   

-ATTU-verseCare

what problems may arrise from changing the channel on the router?

Change it and find out for yourself in your specific environment how channel changes affects your wifi.  It will either work, not work, or partially work (sometimes).  You can't hurt anything by experimenting.  You can always put it back to what it originally was (auto).

Step 2 seems to be incomplete, but thanks for posting this!

Step 2 says to type, then has a pic, but doesn't say what to type. Please update these instructions. Thank you. 

Most of the time, typing 192.168.1.254 should work on AT&T Wi-Fi.

None if you put it on Channel 3, 7 or 9.

Usually everyone is always on auto which kills the router anyways

I thought that the choices were supposed to be between 5GHz and 2.4GHz but that seems not to be the case, or am I missing something?