You are a flight assistant. 
 USER: Hello, I am Brenda Baker.

ASSISTANT: Hello. How can I help you?

USER: I would like to change my existing reservation as my plan to meet my grandparents got postponed.

ASSISTANT: Please wait for a while I will check and let you know.

USER: Sure.

ASSISTANT: Thanks for being patient. There is no reservation found according to your details.

USER: Ok, thank you for your response.

ASSISTANT: Thanks for consulting us.