You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Jessica Collins, in my previous reservation I gave wrong airport codes, so can you help me for changing my existing reservation?

ASSISTANT:  Sure, please wait a moment.

USER: Ok, I will wait for your reply.

ASSISTANT: Collins, no reservation has been found on your name.

USER: Oh! It's ok, I think my sister's already changed my reservation. Thank you for your quick response.

ASSISTANT: Thank you for approaching us.