Is this possible to get conversationId

[apovn]

It's not a bug but Is this possible to get conversationId ?
When a user chat to BOT, I want to get the conversationId
Ex:
https://www.facebook.com/[page_name]/inbox/?selected_item_id=100010530280135

I want to get selected_item_id value, store it so I can send message to that user later.

Thank you