How we change what others think, feel, believe and do
Get others to do as you want by pointing out that a good person would do what you suggest should be done.
You can frame 'good' as any positive attribute, typically indicating this as some form of action that is both socially desirable and, of course, what you want them to do.
You remind me of Mike. Lovely guy, always ready to help. Could you lend a hand?
I can see you're a kind person. Would you like to contribute to our collection?
Oh, you're from Birmingham. Lovely place. Lovely people. I'm sure you'll want to join in.
Altercasting 'casts' another person into another (alter) role, suggesting that they are (or may be) like a person you may describe.
What effectively Positive Altercasting does is to hold up an image of a socially desirable person who sustains shared values that include doing as you are suggesting. This implies that if they do as you ask, they will be like this good image, and that the result of following social rules would be that other people would also approve of their actions. Esteem from others is a very important need for many people, making the thought of being admired particularly powerful. The result should be that the person takes actions that may result in social approval.
Positive Altercasting, or 'Altercasting (negative)', is the third of the 64 compliance-gaining strategies described by Kellerman and Cole.
Kellermann, K. & Cole, T. (1994). Classifying compliance gaining messages: Taxonomic disorder and strategic confusion. Communication Theory, 1, 3-60