Field Symbol issue

Hi,

I am using field symbols for storing name in f_zzname field.

first of all I am assigning component 86 (which is zzname) of <wa_covp_ext> to <f_zzname>.

and then selecting sname in <f_zzname> from pa0001 table.

but then value of this <f_zzname> is not reflecting in <wa_covp_ext>.

Finally I want to get the zzname value in <fs>.

Can anyone help with this?

LOOP AT <fs> ASSIGNING <wa_covp_ext>.

ASSIGN COMPONENT 86 OF STRUCTURE <wa_covp_ext> TO <f_zzname>.

IF sy-subrc = 0.

ASSIGN COMPONENT 158 OF STRUCTURE <wa_covp_ext> TO <f_pernr>.

IF sy-subrc = 0.

ASSIGN pa0001-sname TO <f_zzname>.

SELECT SINGLE sname INTO <f_zzname> FROM pa0001

WHERE pernr = <f_pernr>

AND endda GE sy-datum

AND begda LE sy-datum.

IF sy-subrc EQ 0.

MODIFY <fs> FROM <wa_covp_ext>.

ENDIF.

ENDIF.

ENDIF.

ENDLOOP.