plan to holdUsed after an event or gathering to say that someone plans to hold or host it. 予定だ means “plan to” or “be scheduled to,” and the ending can change for politeness, such as 予定です or 予定なんです.
JA: 来月、友達のためにパーティーを開く予定だ。
EN: I plan to hold a party for my friends next month.