After the product is released in the market, its maintenance is done for the existing customer base.
Once in the production environment, the system will suffer modifications because of undetected bugs or other unexpected events. The system is evaluated and the cycle is repeated for maintaining the system.
As we can see the below diagram, BA is involved in driving business requirement and converting them to solution requirements.
He is involved in translating the solution features into software requirements. Then leads in analysis and designing phase, dictates in code development, then follows the testing phase during bug fixing as a change agent in the project team and ultimately fulfills the customer requirements.