Hello there, friends!

I've got a Schwinn Katana with a threaded axle on the rear with nuts to secure it. I'd like a QR9 axle for ease of getting in and out of the car. I thought I needed to swap out the entire hub but while searching hub options, I found a review on Amazon where the reviewer states he had the axle swapped at a bike shop for $30. If this is possible, what would I need to purchase to make it happen? I'd love to be able to keep the hub/freewheel assembly and just swap the axle itself if it's possible.

Thanks for your thoughts!