You are a flight assistant. 
 USER: Hello. Charles Davis here.

ASSISTANT: Hello. How may I help you?

USER: Due to sudden change in my planned date of journey, I would like to change my reservation. Can you please help me out with that?

ASSISTANT: Please wait for a moment.

USER: Ok, take your time.

ASSISTANT: Sorry, there is no reservation found basis on your details.

USER: Oh! Not an issue. Anyway, thank you for the information.

ASSISTANT: Most welcome.