What are the differences between calling a program, transaction ‘with return’ and ‘without return’ and how can each be accomplished?

• Program

-SUBMIT <rep>|(<field>) [AND RETURN] [<options>].

If you use AND RETURN, the system stores the data of the calling executable program and returns to the calling after processing the called program. The system resumes executing the calling program at the statement following the call.
If you omit the AND RETURN addition, all data and list levels of the calling program (the entire internal session) are deleted. After the called executable program has finished, control returns to the level from which you started the calling program.

• Transaction

-CALL TRANSACTION <tcod> [AND SKIP FIRST SCREEN] [USING <itab>].

This statement saves the data of the calling program, and starts transaction <tcod>. At the end of the transaction, the system returns to the statement following the call in the calling report.

-LEAVE TO TRANSACTION <tcod> [AND SKIP FIRST SCREEN].

This statement ends the calling program and starts transaction <tcod>. This deletes the call stack (internal sessions) of all previous programs. At the end of the transaction, the system returns to the area menu from which the original program in the call stack was started.