iwc IW5449 Operating Instructions Manual page 17

Time setting
14 | 15
Pull out the crown to position 1. With the crown in this position, you can
now set the time. You must push back the crown to position 0 before
wearing the watch.
Please note:
If you need to move the hands backwards (e.g. at the end of Daylight Saving
Time, if the movement is running fast or when setting the time to a different
time zone), you must first turn back the hands by about 30 minutes more
than required, and only then set them to the correct time by turning them
forwards.
If you do not do this, then the minute repeater's striking mechanism will
require about 15 minutes before it is once more correctly synchronised with
the movement. No defect will occur as a result of this.