Implement the Project
Implementation is "show time". This is the phase where you deliver the project product to the customer. This phase may be a part of the execution process depending upon the type of project and project deliverables. But generally, it is the customer "sign-off" phase. It can be full of interesting surprises if the customer has not been adaquately included in the project planning and execution phases.
Project Customer & Stakeholders
Customer acceptance and signoff
This phase is a simple one if the project deliverables meet the customer expectation. If they do not it may mean a return to the execution process.