You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What assistance do you require from our agency?

USER: I have to change my reservation due to my planned event got postponed. So please help me with that.

ASSISTANT: Sure, I am happy to assist you with that. Can I know your full name with which you have reserved the past ticket?

USER: Thank you. Please check the reservation with my name Helen Lewis.

ASSISTANT: Ok, please allow me a minute to check your ticket status.

USER: Sure, take your time.

ASSISTANT: I am sorry to tell you that, when I have checked in our portal, I didn't found any active reservation with your name to do modifications.

USER: Oh! It  may not be booked properly. Anyway, thank you for your time.

ASSISTANT: It's my pleasure. Thank you for approaching us.

USER: Most welcome.