In a pseudo-conversational browse application, one program might open a stream or cursor, FETch a few (but not all) of the response rows, present them to the screen, and then RETURN to CICS (specifying the transid associated with the next program that is to be given control upon the request of the terminal operator).
If the next program is to operate against the same stream or cursor (for example, FETch and present another screen full of data), the program must be the same compile unit.
In this way, the previous execution of the program passes parameters to subsequent executions, and the program is coded to determine if the execution of the program is the first or a subsequent execution, and to process appropriately.