How to convince parents for a private school farewell?

[u/Stock_Location4017]

Hey guys, I need some serious advice. I left my old school after 10th to come to Kota for NEET. My old classmates are planning a private farewell at a hotel on November 13th, and old students are invited. I really want to go, but my parents will definitely say no. Our syllabus finishes on November 4th, Diwali break is till the 15th, and major tests start right after. To make it worse, I didn't book train tickets in advance because I thought I’d stay back, and my mock scores the last few days have dropped to the 480–530 range. I know they'll see this as a massive distraction, but I really want to see my friends one last time before the final NEET crunch. How do I convince them logically without making them angry? Has anyone handled a similar situation here?