We don't have a set price to quote here without seeing the door - panel replacement runs a wide range depending on whether we're matching one section on a door that's still in production or hunting down a panel for a model the manufacturer stopped making years ago. That second case is common in Reese, where a lot of doors are original to houses built in the early-to-mid 1970s. If your door is a common size and the manufacturer still sells that panel profile, it's a straightforward swap. If it's not, we may end up quoting a full door instead of chasing a discontinued part, because sourcing a single obsolete panel can cost more than replacing the whole thing. We'll tell you which situation you're in before we start work, not after.