How do I replace this? Meaning the trim kit? Call Delta tech service and let them see the picture. They should be able to identify what you need to do and/or the proper trim kit for the valve.

How do I replace this? Meaning the entire valve? You do it from the backside of the bathroom wall, cutting the wall open and replacing the valve from the backside.

Thank you! I’ll reach out to delta. We just wanted to change the turn. It’s a concrete wall, so hopefully all we need to do is trim replacement.. but when we pulled off the old delta trim the screws where not in the same places as the new delta trim.