You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you out?

USER: Joseph Gonzalez here, I need to change my reservation as my plan to go for trekking got postponed. Can you help me?

ASSISTANT: Sure, I will help you in changing the ticket. May I know your name please?

USER: I have already mentioned above.

ASSISTANT: Sorry, there are no reservations found in our database.

USER: That's Ok, thanks for your response.

ASSISTANT: Thank you for reaching us.