When the knowledge base does not have the answer, the chatbot refers a human agent. However, if the user sends a message, the chatbot again continues to send a message. Is there a way to end the workflow for lets say 5-10 mins so that the chatbot does not enter the workflow again if the user sends a message within that time span?

Right now there is no human in the loop feature but you can try setting a keyword trigger so that the bot only starts if the user mentions a particular word