Quality Assurance Manager (QA Manager) defines the process to be followed at each phase of SDLC. He defines the standards to be followed, the documents to be maintained and sets the standard for the product.
Where as it is the Project Manager’s responsibility to ensure that the things defined by QA manager are being implemented. He develops the product from start to finish with his team and ensures that the product which is to be rolled out is Defect free and it reaches the standards and views defined by QA Manager.
QA managers can audit the process for certain time periods which are being handled by the Project Manager.