Hi Madelyn! I'm so sorry, but, could you clarify your question? Are you asking about the switch over lever that changes the water flow from the faucet to the shower head? Or is it something else?
There must be some kind of lever or pull to change the direction of the water flow? Do you have a picture you can share so we can help you figure this out?
If you already have the existing shower head, there is a pull on the bathtub spout that changes it from tub to shower.
try using some WD 40 on the lever let it sit overnight then try again. Sometimes it takes a couple of shots of WD40.
There is usually a ring around the faucet you pull down to get shower flow and then push up to get bath tub flow. If this is not the correct answer to what you are trying to do please ask again with more detail and we will try our best to get you an answer
Hi Madelyn: If you are talking about shutting off the shower head and using the tub nozzel, there should be a lever, or, some just push or pull. It depends on what type of shut off you have.
Spray it with some WD-40 And jiggle it up and down a few times to work the WD-40 into the mechanism. You gotta do this every 6 months. Even with locks and those darn One Knob Faucets in the Sink, you gotta use WD-40 regularly.
If you have an old claw foot tub and are wanting to add a shower, you buy a kit to add to the tub..... https://www.amazon.com/s?k=clawfoot+tub+shower+kit&crid=2XR4I3EEP7WLK&sprefix=claw+foot+t%2Caps%2C298&ref=nb_sb_ss_sc_1_11 if the wall is not tiled, I would also get the 360 degree shower curtain to fit into the tub to prevent floor and wall from getting wet.