Finding the right word to mean the same thing as "particular date" can be a challenge, but there are quite a few suitable synonyms to choose from. You could use the term "specific date," "exact date," "fixed date," or "appointed date." Another possibility is "specified date," "target date," or "chosen date." If you want to be more formal, "designated date," "assigned date," or "scheduled date" could be a good fit. Whatever synonym you choose, it's important to consider the context and tone of your writing to ensure that you're communicating your message effectively.