So, when can you do it?

Your agency asks if you can interpret at 1:00. You reply that you aren't available until 3:00. The agency says they will call the hiring organization to see if they can accommodate your schedule.

You didn't mean that you wanted the agency to change the appointment time to accommodate you. You were only telling them when you could work.

Do you
-clarify with the agency?
-accept the job when they change the time?