You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: I am Dennis Garcia, my birthday party place is changed. So, can you help me in change in existing reservation?

ASSISTANT: Sure, please wait for a moment, I will get back to you.

USER: Sure, I will wait.

ASSISTANT: Thanks for waiting, Unfortunately we have not found any flight reservation with your given name.

USER: Thanks for your response.

ASSISTANT: Thanks for choosing us.