The PMP certification is valid for three years after the year of certification. As an example, if Joe Smith became certified in July 1st, 2015, the PMP certificate will be valid till July 1st, 2018. The certificate is valid for exactly three years from the day of certification. Extending the certificate for a period of three years requires furnishing proof of sixty PDUs.
If an individual is unable to provide proof of 60 PDUs in the three year period, her certification will be suspended for a period of one year. In the above example if Joe does not provide evidence of 60 PDUs till July 1st, 2018, his certification will be suspended for a period of one year till July 1st, 2019. During the suspension period, the individual may not use the PMP credentials. However during the suspension period, the individual can submit the evidence of 60 PDUs to retain her PMP credentials.
If an individual is unable to provide this evidence during the suspension period, she will be required to go through the process of PMP certification again like a fresh applicant.