How to ladder reset

Set up the new date to start ladder
d2cs.conf

# ladder start time
# format: yyyy-mm-dd hh:mm:ss
# be carefull:
# all chars created before this date will revert to non-ladder chars
ladder_start_time    =    ""

All characters created before that date will convert to non ladder.

Delete ladder.D2DV from ladder directory

The simplest way is to delete/move files form charsave/charinfo/ladders