The in-person exams are given in slots. PearsonVue clearly states if you arrive late to the exam (which is 30 minutes prior to actual exam time), they will consider you a no-show and you will forfeit the exam fee and have to reschedule. I do not know what the rules are for the at-home exams. You will have to contact the exam provider for that information.
Hi Smitha.
The PMP exam is timed using software; you get 4 hours from when you start to answer all the questions. If you start 15 minutes later than the scheduled time, you ran the risk of been locked out of the exam. Therefore, I strongly advise you to be on time. The risk of starting 15 minutes late is much higher than the reward, it's not worth starting late.
Best.
Training for Project Management Professional (PMP)®, PMI Agile Certified Practitioner (PMI-ACP)®, and Certified Associate in Project Management (CAPM)®