Is there a way to report someone after the end game screen?

Just had a game today where I would constantly get DC my game would freeze and id instantly get sent straight back to the reconnecting page without exiting the game every time id engage on my lane opponent with a stupid application error Id reconnect and I was dead. I know what it is and who did it since it only happened in laning phase then id constantly get the same message when trying to reconnect back into the game. I know its not a league error or my pc since I've seen streamers have this happen to them with the same error msg. Since I kept getting cut off from the game I wasn't able to reconnect back into the game fast enough to get the end game screen to report the person so I was wondering if I could do so even after the end game screen?