how to read a line of a ASSIGN gr_outtab->* TO <lt_outtab>

hello folks i'm a little bit stuck with finding a way to read a work area after an assign

i have declare

FIELD-SYMBOLS:
<lt_outtab> TYPE STANDARD TABLE

data GR_OUTTAB type ref to data.

ASSIGN gr_outtab->* TO <lt_outtab>.

after the assign how can i loop on <lt_outtab>?

Thanx