Teachers can easily modify due dates for individuals to account for IEPs, personal circumstances, etc. This feature works only in Range courses* as Continuous enrollment courses have suggested due dates and not hard deadlines.
Due dates for activities in Range enrollment courses* are assigned to each individual activity in the Activity editor > Settings > Activity settings card. If you want to make changes to the due date of multiple activities at once, you can Remove due date and/or Allow late submissions with Bulk edit in the Editor > Activity list.
*Range enrollment is the default course schedule in Buzz and means that the course is set to run for all students using the same start, end, and activity due dates which are specified by the teacher/school/district. Continuous enrollment courses are the other type of schedule available in Buzz.