Question special

We have a different discussion already in progress regarding unofficial communication after an interview, focused on how an applicant might communicate where they will potentially rank a program. Relatedly, how do Second Look Days affect how programs rank applicants? How does one ask to attend one? If information is not available on a program's site about these optional visits, what are appropriate avenues to ask about going on a Second Look Day? Do Second Look Day visits affect how a program ranks you? This is highly variable per specialty, so general advice overall and specifics about specialties you know will be helpful.