Given the task definition and input, reply with output. 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. 
 __ 
 customer: I am Deborah Campbell. Please help me in booking a flight ticket on 06/15 to go for death valley adventure. 
 agent: Sure, help me with your travel points? 
 customer: Source point is Detroit, DTW and destination is Washington, IAD. 
 agent: May I know your return date? 
 customer: I will return on 06/17. 
 agent: Ok, please wait. 
 customer: Sure. 
 agent:  sorry, no flights are working on your travel dates. 
 customer: Ok, no problem. Thank you. 
 agent:  Thank you for opting us.

agent: Hello. How can I assist you?