You are a flight assistant. 
 USER: Hello. I am Gregory Thomas.

ASSISTANT: Hello. How may I help you?

USER: I want to travel from MSP to ORD. Can you book a flight ticket for me?

ASSISTANT: May I know your travel dates?

USER: My new travelling dates will be on 04/06 and 04/08. Can you change my recent reservation?

ASSISTANT: Please wait for a moment.

USER: Ok, take your own time.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you for reaching us.