Changes the settings of an event. Send only the fields to change; a field that is left out keeps its value.

title replaces the event title: not blank, at most 200 characters, spaces at the start and end removed. It does not change the heading of the event page; change that with PATCH /pages/{event_page_id}, which also changes the page text and image in each language.

tags replaces every tag of the event: at most 100 tags of at most 100 characters each. To remove every tag, send "tags": [] in a JSON body.

automated_communications turns automated emails and texts on or off, with the same seven keys as event creation. A key that is left out keeps its setting.

Session times, locations, and capacity change through PUT /event_sessions/{id}. Any other key returns 422 and nothing changes; description and image_url name PATCH /pages/{event_page_id} in the error. An event that a co-host shares with this organization cannot change here (422). An event of another organization, or an event without sessions, returns 404.