How do I ask for an informational chat? after 17 years as a security officer

I want to talk to people in a new field but I hate cold messages. I have been trying to stay organised about it. Some people reply with short answers. How do you phrase the request?

I wrote three short lines: who I am, why them and a small ask for fifteen minutes. About one in four said yes.

Follow up with a thank-you and a short update. One of my chats led to a referral a month later.