Defroster Hose Removal

I worked in Chrysler Dealer Parts Departments off and on since the 1970's. And I'll admit, I'm not very mechanically inclined. But I do know where things go. I need to know how to get the defroster hoses unhooked from the dash vents on my 1971 Demon 340. They're clipped on a certain way and I can't figure out how to remove them. Thank you everyone.