postulator
noun
pos·tu·la·tor ˈpäs-chə-ˌlā-tər 
: an official who presents a plea for beatification or canonization in the Roman Catholic Church compare devil's advocate
Example Sentences
Recent Examples on the Web Medical experts can’t have any contact with the postulator. 
Washington Post, 11 May 2017 People handling Casey's cause for canonization, called postulators, continue to gather documentation of healings attributed to Casey, which will be studied in Rome. Meg Jones, Milwaukee Journal Sentinel, 4 May 2017 A postulator, the person assigned to present the cause, is assigned and collects public and private writings, interviews people who knew the candidate, and researches the person's life. Jackie Snow, National Geographic, 2 Sep. 2016
Washington Post, 11 May 2017 People handling Casey's cause for canonization, called postulators, continue to gather documentation of healings attributed to Casey, which will be studied in Rome. Meg Jones, Milwaukee Journal Sentinel, 4 May 2017 A postulator, the person assigned to present the cause, is assigned and collects public and private writings, interviews people who knew the candidate, and researches the person's life. Jackie Snow, National Geographic, 2 Sep. 2016 Word History
First Known Use
1714, in the meaning defined above