You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do for you today?

USER: Could you please help me to update my travelling dates in existing reservation ?

ASSISTANT: Sure, may I know your good name please?

USER: I am Donna Anderson.

ASSISTANT: Please wait for some time.

USER: Sure.

ASSISTANT: There is no existing reservation found on your name in our data base.

USER: Ok, not an issue.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your information.