A return statement consists of the symbol RETURN, possibly followed by an expression. It indicates the termination of a procedure (or a module body), and the expression specifies the value returned as result of a function procedure. Its type must be assignment compatible with the result type specified in the procedure heading.

Function procedures require the presence of a return statement indicating the result value. There may be several, although only one will be executed. In proper procedures, a return statement is implied by the end of the procedure body. An explicit return statement therefore appears as an additional, probably exceptional termination point.

An exit statement consists of the symbol EXIT, and it specifies termination of the enclosing loop statement and continuation with the statement following that loop statement.

Source:

Wirth N: Programming in Modula-2, 3rd ed. Springer Verlag, Berlin, 1985.
Stony Brook Modula-2 documentation. Used with permission. Note: Stony-Brook M2 offers an extended syntax with features not described here. Stony Brook M2 users are encouraged to visit the Stony Brook website and to consult the Stony Brook help system.