Your distribution channel has to do with how you get your product or service offering. That which you are providing to your customer, to your market.
Consider that you are running a fitness company. In this case your channel to market might need to be physical. You might require equipment and a gym where people can come and train. Depending on your offering though you might want run your fitness company virtually and train people over the internet with the equipment that they have available in their homes.
A change in your business model’s value proposition could therefore affect your distribution channel.