You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my reservation which is done recently due to some problems, can you please help me?

ASSISTANT: Sure, I will help you. May I know your name?

USER: Sure, my name is Gregory Mitchell.

ASSISTANT: Give me a minute, please.

USER: Sure, I will wait.

ASSISTANT: Thank you for waiting, there is no reservation found on your name to change.

USER: Ok, no problem. Anyways, thank you for your service.

ASSISTANT: Thank you.