Reschedule works slightly differently depending on whether the task has any
work done on it ir not. If there is no work done, it applies a "Start No
Earlier Than" constraint to the task of the designated resume work date,
effectively rescheduling the task to start on that date. IF there has been
some work done - say, for example, there's a 5-day duration task that was
supposed to begin last Monday and it's now late Friday afternoon. Work was
done Monday and Tuesday but then stopped, the resource called in sick, so it
has an Actual Start of Monday, an Actual Duration of 2 days, and a Remaining
Duration of 3 days. Reschedule Work (to after today) will split the task at
Tueday, leaving Monday and Tuesday's work where it is, and shift the
remaining 3 day out to resume on next Monday, with those 3 days scheduled to
run on Mon, Tue, and Wed of next week. For the first task, the one with no
work at all, the Stop and Resume fields will be empty and the rescheduling
is accomplished through the constraint, same as manually entering a start
date. For the second task, the date marking the end of the work performed
populates the Stop field and the date the remaining work begins populates
the Resume field. In both cases your Baseline (you do have a baseline,
right?) will retain the originally scheduled start and end dates for
progress reporting and comparison purposes.