The domain of the COBIT framework that addresses the maintenance and change management of existing systems to ensure alignment with business needs and objectives is 'Acquire and implement.' This domain specifically focuses on the process of acquiring and implementing new IT solutions as well as maintaining and making changes to existing systems. The other domains, such as 'Plan and organize,' 'Deliver and support,' and 'Monitor and evaluate,' do not specifically cover the aspect of change management and maintenance in the way 'Acquire and implement' does.