We have a sprayer on our kitchen sink, and all of a sudden it won't switch back to the water coming out of the faucet. As soon as I turn the water on it comes out of the sprayer. I tried turning the valve the spray hose goes into but it didn't do anything. I can't fix the sprayer, and I don't see the part that switches the water to the faucet. Is there something below the sink I can disconnect until I get a new sprayer to have the water come out of the faucet? ? Does the water have to be shut off to the apartment to change the sprayer, or just the water knob turned off at the sink?

I'm leaving about 5 EST, and I need to fix this for my mom's caretaker before if possible so she can use the sink without the sprayer---HELP---Please!!!