1) Emcee 2) Preside 3) Ref 1) Perform 
• (v. t.) To discharge, perform, or supply, as an official duty or function. • (v. i.) To act as an officer in performing a duty; to transact the business of an office or public trust; to conduct a public service.
Of·fi'ci·ate intransitive verb [ imperfect & past participle Officiated ; present participle & verbal noun Officiating .] [ Late Latin officiare . See Office .] To act as an officer in performing a duty; to transact the bu...
[v] - act in an official capacity in a ceremony or religious ritual, such as a wedding 2. [v] - perform duties attached to a particular office or place or function