You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, may I know your trip dates?

USER: I want to change my reservation. Can you please check for this?

ASSISTANT: Sure, can you please tell me your name to update your existing reservation details?

USER: Myself Pamela Perez.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no reservation with your name in our portal to make changes.

USER: Not a big deal, anyhow thank you very much for checking the reservation status.

ASSISTANT: You are welcome, have a great day.