The phrase "on the agenda" refers to something that is scheduled or planned to be discussed or addressed in a meeting or similar gathering. Synonyms for this phrase include "scheduled," "planned," "slated," "arranged," "programmed," "booked," or "organized." All of these terms convey the idea of something that has been decided upon in advance and is intended to be included as a topic of discussion or action at a particular event. Using these synonyms can help to add variety and clarity to written or spoken communication and make the meaning of the message more explicit and easy to understand.