You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Myself Deborah Campbell due to some meeting's, I am going to change my existing reservation. Can you please help me in changing the reservation?

ASSISTANT: Please wait for a moment.

USER: Sure, I will wait for your response.

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

USER: Not a big deal, anyhow thank you very much for your service.

ASSISTANT: Most welcome.