When you have an interview, wait until the interviewer (the host) tells you where to sit. Remain standing in front of your chair, until the interviewer moves to take his or her seat. Lower yourself into your seat at the same time. If someone walks in and the interviewer introduces you, stand up to greet that person.
The same is true for a sales call or any business meeting. Wait until your host tells you where to sit. Sit when your host sits and stand to greet any newcomers.
Courtesy of Culture and Manners Institute