Q: In this task, you're given a dialogue between a customer and a flight booking agent with a gap in the conversation. Your job is to find the answer of the previous dialogue. Avoid using irrelevant extra information while creating the answer. The answer should be relevant to the question before the blank. If you fill the blank with a question, it should have an answer from the agent in the given dialogue. Fill the gap marked with underline.
customer: Hi. 
 agent: Hello, how may I assist you? 
 customer: I am heading from Dallas & Fort Worth to meet my manager at San Francisco. Can you help me with the booking? 
 __ 
 customer: I intend to start from DFW to reach SFO. 
 agent: Please share me your trip dates. 
 customer: They are on 09/09 and 09/11. 
 agent: May I know your good name? 
 customer: My name is Karen Wright. 
 agent: There is no flight on your details. 
 customer: Ok, thank you for the information. 
 agent: Thank you.
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
agent: Sure, may I know your airport codes?