Note! Charts do not have a date range, only classes, goals, class schedules and goals schedules can have a date range.
The date range for a single class schedule can be changed as follows:
Note! If you change the date range for the class schedule to be more narrow or exclude the date ranges of individual classes, all data (scores, comments) for those classes outside the class schedule range will be lost.
The default end date for every class schedule is Sept 1st of the following year.
Also remember that changing a class schedule that is applied to multiple charts will affect all those charts at once.