Newbie question - appropriate way to access passed table in a subroutine.

Hello,

I am trying to write a subroutine in a function module that will process and update the contents of the passed in table t_dep (below). I am missing something and would appreciate if someone could point it out and or make reccomendations. Code snippit below.

FORM proc_dep using i_cm_from type datum

i_cm_to type datum

changing t_dep type zhdependent.

FIELD-SYMBOLS : <fs_DEP_DATA> LIKE T_DEP.

LOOP AT t_dep ASSIGNING <fs_DEP_DATA>.

Thank you,

Andre