You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Sandra Davis.

ASSISTANT: Sandra Davis, how may I aid you?

USER: I am willing to change my reservation. Can you please help me for this?

ASSISTANT: Sure, please hold on for a while.

USER: Ok, I will wait for your response.

ASSISTANT: Sorry, no reservation is available by your name.

USER: Not an issue, anyhow thank you very much for your service.

ASSISTANT: Thank you for reaching us.

USER: You are welcome.