Delegate.
Synonyms:
deputy, legate, proxy, representative, substitute.
These words agree in designating one who acts in the place of some other or others. The legate is an ecclesiastical officer representing the Pope. In strict usage the deputy or delegate is more limited in functions and more closely bound by instructions than a representative. A single officer may have a deputy; many persons combine to choose a delegate or representative. In the United States informal assemblies send delegates to nominating conventions with no legislative authority; representatives are legally elected to Congress and the various legislatures, with lawmaking power.