Custom page template with one column

Hi, I'm working on a custom page template that has one column. My main site uses the 2 column setup, but I'm trying to figure out how to just show one column for a custom page template. I removed the side bar, but now the main content is just on the left side. I've created child theme already. I know there's a way to show one column for my entire website, but I just want to have one column for a custom page template. Is there a way to do that? Any help would be greatly appreciated. thanks.