Of course volunteers call in sick, go on vacation, or quit altogether. Rather than deleting each individual assignment, VSys gives you a link on the person's Assignments panel: Cancel... From there, selecting Cancel for time period prompts you for the date range for which the assignments should be cancelled. All assignments on or between these dates, including those within a recurring assignment, will be marked as "Cancelled by staff member" or "Cancelled by volunteer" depending on the option you select. This include assignments across multiple jobs.
Recurring assignment schedules are not affected, only the actual assignments within them.
Cancel all cancels all of this person's assignments from the current date forward. All assignments are cancelled, including the recurring assignments themselves.
When you make person inactive or one of several other statuses look for a link to cancel their assignments or associations at that time.