Increasing WiFi Signal Strength

So, I've seen Xfinity commercials lately with tips for increasing WiFi signals in the home. One tip is to not place the modem near large appliances, such as refrigerators. Our modem has always been right next to our refrigerator, and I'm assuming we'd get a stronger (more stable) signal if the modem was moved to another location. For the most part, we don't experience many issues with the current configuration. We used to have a separate business line for internet when my wife worked from home. Can I easily switch out the current active line to that connection in order to move the modem, or is that something I should have a qualified technician handle? The room I'd want to move the modem to is right on the other side of the wall from where it is currently located in the kitchen.