You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: Laura Jackson here. I would like to change my existing reservation today due to some office work, can you help me?

ASSISTANT: I understand your request and will be happy to help you.

USER: Ok, I will be waiting for your response.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes.

USER: Oh! That's very sad to know. Anyways, thank you for checking with it.

ASSISTANT: Thank you for consulting us. If any questions arise, please feel free to contact us at any time.

USER: You are most welcome.