This was an initial HM screen. The guidance from recruiting was that we would discuss the role and some projects, and my background. The HM had a conflict and sent one of his direct report managers to the interview instead. The interviewer proceeded to ask a series of rapid fire technical questions. I felt I did reasonbly well but since I was not prepared for this type of interview, I did not do as well as I could have. I also felt that it would have been more appropriate for the HM to reschedule, rather than send a direct report.