Yes. If you have sat a process or project management certification exam once and not passed, the task now is diagnosis, and rehearsal under real conditions is built for exactly that. A practice sitting lets you rehearse the timing and pressure that may have cost you, and the review points to the specific weak areas to rebuild — with no claim about how a second attempt will turn out.
A failed sitting is data, not a verdict, and the best use of it is to treat it the way PRINCE2 treats a closed stage. Its principle of learning from experience says you record what a stage taught before you plan the next one, in a lessons log, so the same mistake is not repeated. A retaker can keep that log for themselves: what actually went wrong last time — ran short of time, misread the long scenarios, guessed across one domain — and aim the next round of practice straight at it.
Writing your own lessons log from a process certification review
The review is where the log gets written. Working back through a sitting, you are looking for the pattern behind the misses, not merely their count: a run of wrong answers in one domain says the knowledge is thin there; a scatter of near-misses across several says the trouble is reading the scenario, not the content; a clutch of questions rushed at the end says pacing let you down. Each pattern points to a different repair, and the per-option marking — which reasonable choice you took, which you should have — is what lets you tell them apart. That is diagnosis you can act on, rather than a bare sense that it went badly.