3.5Rescheduling & Managing Changes
The essentials in 30 seconds
- No project runs exactly as planned: knowing how to reschedule is a key skill; 'Update Project' reschedules unfinished work after a given date.
- You update actual progress, then let Project realign the linked successors — instead of moving the bars by hand.
- Splitting represents a task interrupted then resumed; you use float before compressing the critical path.
Running mini-case — Meriem absorbs a site contingency
Meriem, a BTP project manager in Algiers, faces a classic contingency: a concrete delivery is postponed and the foundations run a week late. Her temptation would be to move all the following tasks by hand in the Gantt chart — the mistake to avoid. She first updates the actual work of the foundations, then lets Project automatically realign the linked successors: the impact on the finish date appears at once. For a waterproofing task put on hold during bad weather, she splits it: the bar is cut into dotted lines, the total work does not change. She notes the reflex: enter actuals, let it realign, then decide by using float before compressing.
Standalone case for this section: it comes back in the lesson, the diagram, the script and the 48h challenge of section 3.5.
1. The rescheduling tools
No project runs exactly as planned: delays, absences, bad weather. Knowing how to reschedule is a key skill. The Update Project function reschedules unfinished work after a given date, and splitting makes it possible to interrupt then resume a task.
2. Enter actuals, let it realign
Good practice: update actual progress, then let Project realign the remaining work according to the dependencies — the impact on the finish date appears immediately. Moving the bars by hand creates constraints and breaks the logic of the schedule: that is precisely what to avoid.
3. Decide: float first
Once the impact is measured, Meriem decides. She uses the float to absorb small contingencies without touching the critical path, and only 'catches up' (compression) if the critical path slips. The baseline remains the compass: you compare, you decide, you do not suffer.
🔎 Concrete example — 🔎 Concrete example — Do not move by hand
Meriem hesitates between two reflexes in the face of the foundations' delay:
Linked task late -> update actuals, Project realigns the successors.
Moving the bars by hand = constraints + broken logic.
-> split a paused task (dotted bar).Reading: with links, the automatic recalculation is enough to measure the impact.
Lesson: splitting models a pause cleanly, without lengthening the duration.
Section vocabulary
- Rescheduling
- Adjusting the schedule along the way to account for actuals and contingencies.
Simple example: Meriem reschedules the remaining work after the foundations' delay.
What it is not: a frozen schedule that is never touched again.
Reflex: the schedule evolves → rescheduling.
- Update Project
- Function that reschedules unfinished work after a given date.
Simple example: Meriem reschedules the unfinished tasks after the stoppage.
What it is not: moving the bars one by one by hand.
Reflex: reschedule the unfinished → Update Project.
- Task splitting
- Interruption of a task then a later resumption, represented by a dotted bar.
Simple example: Meriem splits the waterproofing during the bad weather.
What it is not: lengthening the duration to simulate a pause.
Reflex: pause then resume → split.
- Unfinished work
- The remaining part of an unfinished task, which is rescheduled after the tracking date.
Simple example: Meriem reschedules the rest of the foundations.
What it is not: the work already done and validated.
Reflex: what remains → unfinished work.
- Corrective action
- Decision taken in the face of a variance (add resources, shift, reduce scope) to meet the objectives.
Simple example: Meriem reinforces the team to catch up on the critical delay.
What it is not: observing the variance without deciding anything.
Reflex: react to a variance → corrective action.
In practice — In practice — Rescheduling in the face of contingencies
- Update the actual progress of tasks (what is done) before rescheduling the rest, like Meriem.
- Use Project > Update Project to reschedule unfinished work after a date.
- For an interrupted task, split it: the bar is cut into dotted lines to reflect the pause.
- Observe the impact on the finish date, use float and trigger a corrective action if the critical path slips.
Step-by-step script — rescheduling a contingency like Meriem (4 min)
1) Enter the actual progress of the finished tasks. 2) Use Project > Update Project to reschedule unfinished work. 3) Let Project realign the linked successors and read the impact on the finish date. 4) Split the tasks put on hold. 5) Use float, then compress the critical path only if necessary.
Keep this reflex: the tool handles the mechanics of recalculation; the decision stays with the project manager.
Copy-paste template — my rescheduling sheet
Enter : the actual progress of the tasks
Reschedule: Project > Update Project (unfinished work)
Realign : let Project recalculate the linked successors
Pause : split the task (dotted bar)
Decide : float first, compression of the critical path nextA delivery delay
Meriem updates actuals: Project realigns the successors and shows the impact on the finish.
Bad weather
Meriem splits the waterproofing task: the bar is cut into dotted lines, without lengthening the duration.
A global stoppage
Meriem uses Update Project to reschedule all unfinished work after the stoppage date.
A critical path that slips
The contingency touches the critical path: Meriem compresses, after exhausting the float.
✓ Best practices
- Enter actuals before rescheduling the rest.
- Let Project realign the linked successors.
- Use the float before compressing the critical path.
✗ Common pitfalls
- Moving all the following tasks manually.
- Lengthening a duration for a pause (prefer splitting).
- Ignoring the impact of a contingency on the critical path.
Key takeaways
- Rescheduling = adjusting the schedule as actuals and contingencies unfold.
- 'Update Project' reschedules unfinished work after a date.
- Splitting represents a task interrupted then resumed.
- You use float and compress only if the critical path slips.
48h challenge — apply it tomorrow
Like Meriem, take a linked task that is running late: enter the actuals, then let Project realign the successors and note the impact on the finish date. Then split a task put on hold (a dotted bar). Write in one sentence whether you absorb the contingency in a float or compress the critical path — and why.
- I can explain how to reschedule the remaining work.
- I know how to use Update Project and splitting.
- I use float before compressing the critical path.
Frequently asked questions
A task is running late: should you move all the following ones manually?
No, that is precisely what Project avoids. If your tasks are linked by dependencies in automatic mode, simply update the late task (actual work, remaining duration): Project realigns all the successors and shows the impact on the finish date. Moving the bars by hand creates constraints and breaks the logic: you enter actuals, let it recalculate, then decide.
How do you represent a task put on hold then resumed later?
With task splitting: in the Gantt chart, the 'Split Task' tool lets you cut the bar at the interruption and resume it later — the unworked part appears as dotted lines. This is the clean way to model a suspension without artificially lengthening the duration. For a global reschedule, you rather use 'Update Project'.
A linked task runs late: what should you do?