A good project reporting system connects costs, labour, forecasts and billing so reports can be produced with less manual work. Set it up early, give the team clear responsibilities, and use the same information for project and program reporting.
If, during a project, the client realises a mistake in the scope or specs or one is pointed out to the client and the client authorizes or instructs a change …
Projects are complicated. Lots of agreements and changes are constantly made, these should be managed properly.
Document all changes, variations and agreements on your projects. You should put everything in writing.