How to change the default mode of transportation for work/home in Google Maps Go tab?

When you set your home and work settings in Google Maps, it will automatically add them as defaults under the Go tab on iOS. If you add pinned locations, they appear underneath the Home and Work locations. Home and Work are defaulting to driving directions whereas pinned locations use whatever method of transportation you chose when you pinned them. How do I change the method of transportation for the home or work locations under the Go tab?