What if analysis

Yes you can. In fact, from a project manager’s point of view, that is what Primavera is for.

Many people see planning and scheduling software only as a rear view mirror - as a tool to register the past: What activities were acomplished, and when. It´s real power lies in the ability to let you look forward and analize the future effect of your decisions today:
If I apply additional resources (which have an additional cost) to finish a certain activity early, will that result in an early project finish? That’s not always the case, even for critical activities.

Ali
To perform such a "What-if" analysis, you should make a copy of the current schedule, using the P3 Project Utilities. Then, in the new copied schedule, make the original (current) schedule a target schedule.

In the layout you wish to modify, apply the changes (such as you described) and re-schedule the project.

To see how the new "what-if" schedule compares with the original, define a Target Bar in the layout, and place under the Early Bar of the "What-if" schedule.

You can also define Target 1 Early Start & Finish date columns next to the Early Start & Finish date columns for comparison, as well as Finish & Start Variances (T1EF-EF or T1ES-ES), to quantify how many early or late days the activities will finish or start compared with the original schedule.