1. A computer-implemented method for managing user interface (UI) building blocks (UIBB), the method comprising: presenting, by a form repeater UIBB, initial UI representations of structured entities through a graphical user interface (GUI), each initial UI representation comprising one or more fields; receiving a trigger from a user through the form repeater UIBB; determining, based on the trigger, an event condition; and based on the event condition, replacing, by a substitute UIBB, an initial UI representation of a particular structured entity of the initial UI representations of the structured entities with a substitute UI representation of the particular structured entity.