Even when the design has been released for production it cannot be considered to be absolutely final requiring no further changes. Certain problems may be faced during production which may call for changes in design. However before these change are approved their implication and repercussions on quality parameters should be thoroughly gone into by the design and quality engineering departments. Once it is decided to incorporate the design changes necessary amendments should be carried out in all the affected drawings and specifications. Normally the copies of drawings and specifications are held by various departments of the company.