What changeover method replaces an old system with a new one on the same day?

The method that replaces an old system with a new one on the same day is known as the direct changeover method. This approach involves completely switching from the old system to the new system in a single step. It is often regarded as a fast transition since the new system goes live immediately after the old system is taken offline.

One of the key advantages of the direct changeover method is that it minimizes the time employees need to adapt to the new system, as there is no overlap period with both systems operating simultaneously. However, it also comes with significant risks, as if the new system encounters issues or fails, there may be no fallback to the old system.

In contrast, the parallel method runs both the old and new systems concurrently for a period, allowing for comparison and assurance that the new system is functioning correctly before fully committing. The phased method introduces the new system in steps, allowing gradual integration, while the pilot method tests the new system on a small scale before a full rollout. These alternative methods mitigate risks associated with a sudden transition, which is why they are often preferred in complex environments.