According to the PMBOK Guide, the project closing process group consists of two processes: close project or phase and close procurements. The close project or phase process involves confirming that the project or phase scope and requirements have been met, obtaining formal acceptance of the final product, service, or result from the customer, and transferring the ownership and responsibility of the deliverables to the assigned stakeholders. The close procurements process involves completing and settling each contract, including resolving any open items, and closing each contract applicable to the project or phase. Therefore, the project manager should review the deliverable requirements, check the customer approval criteria, and proceed accordingly to close the project or phase. Asking the customer to issue a change request, meeting with the customer to reach agreement on the scope, or contacting the project sponsor for help are not appropriate actions during the closing process, as they imply that the project scope is not finalized or agreed upon, which should have been done during the planning and executing processes. References: PMBOK Guide, Sixth Edition, pages 123-124, 377-378; PMI-PBA Guide, First Edition, pages 209-210.