YOU SAID:

I'm anxiously awaiting the 4th of December due to an appointment

INTO JAPANESE

予約があるので12月4日を楽しみに待っています

BACK INTO ENGLISH

I have a reservation, so I'm looking forward to December 4th.

INTO JAPANESE

予約してあるので12月4日が楽しみです。

BACK INTO ENGLISH

I have a reservation and am looking forward to December 4th.

INTO JAPANESE

予約してあるので12月4日を楽しみにしています。

BACK INTO ENGLISH

I've made a reservation and am looking forward to December 4th.

INTO JAPANESE

予約したので12月4日を楽しみにしています。

BACK INTO ENGLISH

I have made a reservation and am looking forward to December 4th.

INTO JAPANESE

予約しましたので12月4日を楽しみにしています。

BACK INTO ENGLISH

I have made a reservation and am looking forward to December 4th.