[ABAP-OO] Returning vs Changing Method

Hi Experts,

we have many way to change a variable value.

for example:

• me->modif_value( CHANGING field = lv_field ).

or

• lv_field = me->modif_value( lv_field ). "// returning

I would like to know what is the best way to use CHANGING or RETURNING and in which case we have to use it ?

Thank your very much.

Rachid.