I need to switch between dial-up and wireless.?

I have wireless feature on my personal. At my home, I do not have access to cable so I use a dial up connection. When I am traveling, I have access to the wireless feature. How do I switch between wireless connection and dial-up. I’ve actuated the wireless feature at a location which provides internet wireless access this day, but when I try to go on line, the dial-up connection comes up and since I am not connected to a phone line, I don’t reach the internet.