iwc Schaffhausen Mode D'emploi page 22

Setting the time
Pull the crown to position 2. This will stop the movement. To ensure that the
set time is accurate to the second, the movement should be stopped as
the second hand passes 60. You can now position the minute hand exactly
on the minute line. As the hands are moved forwards past 24.00, the
calendar will advance by one more day. The automatic change sequence
can be completed and verified as the calendar advances. Under no
circumstances must the hands be turned back between 20.00 and 2.00.
Important: The crown must always be pushed back into the winding
position before wearing the watch. In this way you will avoid unintentional
adjustment of the calendar.