You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Daniel Martin.

ASSISTANT: What kind of service you are looking for.

USER: I would like to change my existing reservation due to postpone of my trip with family to Philadelphia. Can you please help me?

ASSISTANT: Sure, I can help you in that. Please wait, let me check your reservation status.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry Daniel Martin, there is no active reservation on your name to change it.

USER: No worries, thank you for the information.

ASSISTANT: Thanks for approaching us.