Relegate means assign to a lower position. If the quarterback of the football team stops making decent throws he might be relegated to the position of benchwarmer, while another kid is given the chance to play.
Relegate rhymes with delegate––both words derive from the Latin legare "send." Relegate means to send someone down in rank. Delegate means to send someone in your place to complete a task. In the workplace, managers who can't figure out how to delegate may get relegated to a lesser rank.