Do you ever try and reason with dementia?

No it’s impossible to argue with a person with dementia. You may want to explode but don’t try. It’s a losing battle.
Count to 10 slowly before you react and use that time to do self analysis and realize the absurdity of your interaction. Then continue to listen and politely back out.

My mom has the paranoia. Not sure if dementia is part of it yet, but when she has her paranoid moments, I ask her a little about it, and then try to change the subject. I guess in a way validating what she feels but without feeding too much into it.

Earlier she was thinking people were watching her from her bedroom window. I asked if she saw anyone, and she said she just "knows they're there." I just nodded and said, "Oh." Then I changed the subject and said something about the weather.

Thank you eyerlislash

It's rarely a good idea to try to reason with or contradict someone with dementia. Our reasoning is intact, theirs isn't, and these kinds of conversations go nowhere and are emotionally draining.

If your family member is accusing others of stealing, which is very common with dementia, you can try to divert her attention without reinforcing her opinion that family is stealing from her. "When did you last see it?" or "I recall seeing in somewhere but I don't remember where." Try not to reinforce her accusations of stealing.

I know it feels like the right thing to do to stick up for your family members whom you know are not stealing but again, that's using logic with someone who can't reason. You don't have to agree with her when she makes accusations, just turn the conversation around to something else. If you're desperate, reach for a fib: "Guess who I saw at the grocery store today? Sue Jones! Remember her? She lived 3 doors down from us when we were growing up. She asked about you....." It doesn't matter that you didn't see Sue Jones but it's a tool to put in your toolkit that you can whip out if necessary.

Sometimes i can reason with her..
I think its just best to agree to EVERYTHING. ;(

You can't reason with dementia.

You CAN empathize with the feeling. ' oooh, im so sorry your bracelet is missing and terrible that you think Julie might have taken it. That must be a terribly sad feeling" offer to help her look for lost items

Watch Teepa Snow for good techniques.