You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Charles Lewis.

ASSISTANT: How may I guide you today?

USER: I had planned to go on a trip, but it was postponed due to some reasons. Can you change my recent reservation?

ASSISTANT: Sure, I will help you with that. Can you please share your preferable journey dates? Sorry, I will help you with that. Please wait for a minute.

USER: Ok, take your own time.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

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

ASSISTANT: Thank you for reaching us.