The short answer is, if a Subject Matter Expert provides expert advice that will alter one of the baselines (schedule, cost, scope), then a CR must be submitted and approved before following it.
I am prepping to sit the exam in a few days and what I have learnt is that once the project management plans have not been approved, no change request is needed. If the project management plans have been approved, then you need a change request regardless of who is giving you the direction. Read this is a lot of the explanations PM Prep Cast gave if I got the question wrong.
As I work through mock exams in prepcast I find that sometimes the correct answer when told what to do from a SME is just do it and sometimes it's submit a C/R. In general when do we just do what the SME says without a C/R and when would we need a C/R ?
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