how to recovery wechat deleted chat history

Hello guys, I really want to know how to recover the chat history of a deleted conversation in wechat. my iphone is iphone6 version 8.4.1 wechat version is 6.3.1

I want to recover a recorded voice chat history, but the records are not in other places, they are in the wechat app. what should i do to recover that? i didn't back it up 😟