You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Can you help me to change my reservation?

ASSISTANT: Sure, please mention your name to check your reservation details.

USER: I am Nancy Harris.

ASSISTANT: Thank you. Please be online for a while. I will check your reservation status and get back to you.

USER: Sure, take your time.

ASSISTANT: I am sorry to say you that there is no reservation found under your name in our database.

USER: No problem, thank you for the checking.

ASSISTANT: Thank you for reaching us.