Boy did I just have the following drilled into me during training
Item number 1 FAA Commercial PTS Special Emphasis Areas
Positive Exchange of Flight Controls
During flight training, there must always be a clear understanding
between students and flight instructors of who has control of the
aircraft. Prior to flight, a briefing should be conducted that includes
the procedure for the exchange of flight controls. A positive threestep
process in the exchange of flight controls between pilots is a
proven procedure and one that is strongly recommended.
When the instructor wishes the student to take control of the aircraft,
he or she will say, “You have the flight controls.” The student
acknowledges immediately by saying, “I have the flight controls.”
The flight instructor again says, “You have the flight controls.” When
control is returned to the instructor, follow the same procedure. A
visual check is recommended to verify that the exchange has
occurred. There should never by any doubt as to who is flying the
aircraft