Hi,
Please check whether you have the following steps for table control.
PBO
Loop itab into wtab with *****
Module Show data: Here
Endloop
PAI
Loop itab
Module modify_data:
Endloop
Module show_data.
move watab to (structure used in table control)
Endmodule
Module modify_data.
move (table control structure) to watab
modify itab from watab index tctrl-current_line
if sy-subrc <> 0.
append watab to itab.
endif.
Endmodule
Regards
Anand