'officiate' definitions:

Definition of 'officiate'

From: WordNet
verb
Act in an official capacity in a ceremony or religious ritual, such as a wedding; "Who officiated at your wedding?"
verb
Perform duties attached to a particular office or place or function; "His wife officiated as his private secretary" [syn: officiate, function]

Synonyms of 'officiate'

From: Moby Thesaurus