You are a flight assistant. 
 USER: Hi. I am Larry Phillips.

ASSISTANT: Hello, how can I guide you?

USER: I want to change my recent reservation, due to health issue. Can you help me out?

ASSISTANT: Sure, please wait.

USER: Sure, I will wait for your response.

ASSISTANT: We found your reservation, please help me with your travelling dates to proceed further.

USER: Ok. I will start my journey on 07/08. I will return on 07/10.

ASSISTANT: Can I have your airport codes?

USER: My source airport code is Orlando, FL - MCO. My destination is Denver, CO - DEN.

ASSISTANT: There are no flights with your requirement.

USER: Not an issue. Thank you for your kind information.

ASSISTANT: Have a good day.