Manychat has this feature when someone comes back to chat to the bot after sime time it greets them with their name. It already has their prior info

You can do that now. Save the name as a user variable, then you can check it for a value and greet by name if you have one.

How do you achieve that? do you store it in a table along side with conversation ID or something similar or what?

yeah, how does this work?

Create a user variable called Name. When you prompt for name, Execute code to copy the name from the workflow variable to the user variable. user.Name = workflow.userName Near the beginning of your flow, execute the reverse of that code, to copy from user variable to workflow variable. Then there are a couple of ways to proceed with that. I am showing one approach here.