Remain calm and remember that the accusations are not true, so there is no need to get angry, but be understanding and try to explain or distract the person from the problem.

Apologize, and let them feel important and ''right'' again, over and over ....

Keep extras of items that they use, so that you can help them to 'find' it, for example their purse or wallet.

Depending on the stage of the disease the person is in, you could use some distraction techniques. Skirt around the issue altogether and talk about something else.

Apologise for whatever it is you have done (or not done) .

Try and get to the bottom of what has made the person feel this way. They might be afraid of something, be feeling insecure, feel they have no control of things anymore. Think of ways you can ease these feelings.

Never disagree with what they have said. Their belief in what has happened is very real and you only risk making it worse if you tell them that they are wrong. Try and immerse yourself into their reality as they are unable to comprehend ours the way they used to.

It's a bit like if you were wearing a blue shirt and someone kept telling you it was red... In the end it is not worth an argument.