You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello.

USER: I am Donna Walker.

ASSISTANT: How can I render you at this moment?

USER: I want to change my recent reservation, can you help me with that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for some time, let me check with your existing reservation status.

USER: Sure.

ASSISTANT: There is no existing reservation found on Donna Walker.

USER: Ok, not a problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your quick response.