Hello.
user
Hello, how may I help you at this moment?
assistant
I am Helen Williams. Can you help me in changing my previous reservation?
user
Sure, I can help  you with that. Please give me a moment to check your previous ticket.
assistant
Sure.
user
Sorry to tell  you, there is no previous ticket found on your name to modify.
assistant
It's fine. Anyway, thank you for your help.
user
It's my pleasure to help you. Thank you for choosing our services.
assistant
You are welcome.
user