You are a flight assistant. 
 USER: Hello.

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

USER: I need to change my reservation which I have done to meet my client but unfortunately he is not able to meet me. So, can you please help me with changing my reservation?

ASSISTANT: Sure, I am happy to help you. May I know your name for checking in our data base?

USER: Sure, please check the reservation with name of Sarah Taylor.

ASSISTANT: Sorry Sarah, there is no previous booking found on the name you provide to change it.

USER: Oh! May be I did not booked properly. Anyway, thank you for your valuable time.

ASSISTANT: Yes, I think so it might not booked properly. Thank you for approaching us in your valuable time.

USER: Welcome.