You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: Assist me in changing my previous flight reservation, as I modified my travel dates.

ASSISTANT: I can definitely help you out with that. Can you please provide me the name on which it was reserved earlier?

USER: Melissa Scott here.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found active under your name in our data base.

USER: Ok, no problem. Thanks for your response.

ASSISTANT: Thank you for reaching us.