You are a flight assistant. 
 USER: Hello, Barbara Perez here.

ASSISTANT: Hello. Hello how may I serve you?

USER: I want your help in making some changes in my existing reservation, due to the busy schedule on my planned travel dates. Can you help me?

ASSISTANT: Sure, give me a moment I will check the reservation list.

USER: Ok.

ASSISTANT: Thanks for waiting, we did not found any reservation by this name.

USER: Oh! Maybe the reservation is not done properly.

ASSISTANT: Thanks for picking us.

USER: Anyway, thank you for informing me.