To visit in order to see how someone is doing.
To verify a person's information and record their arrival, such as at a hotel, airport, etc.
To integrate new revisions into the public or master version of a file in a version control system.
To announce or record one's own arrival at a hotel, airport etc.
To contact another person in order to keep the other person informed of one's situation.
To return (a book to a library, source code to a repository, etc.).
To enter solitary confinement at one's own request for protection from other prisoners.
To send somebody to solitary confinement; to make somebody be admitted to solitary confinement.
To agree to purchase some good or service.
To add one's own name to the list of people who are participating in something (including amateur, but not professional, teams)
To add a name to the list of people who are participating in something.