You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. What service you are expecting from our travel agency?

USER: I am Lisa Jones, can you help me for changing my existing reservation?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please provide me some time to check the ticket status.

USER: Ok, I will wait for your reply.

ASSISTANT: Sorry, there is no reservation found on your name in our database to modify.

USER: Oh! It's ok, no problem. Thank you for your services.

ASSISTANT:  Thank you for reaching us. You are welcome.