You transfer your reports internal table data to the function module through SORT_TAB which will sort it and return the sorted output in the same table.
DATA: i_sort type table of RESBK with header line.
...
" transfer your own report's internal table contents to i_sort using statement such as
move-corresponding
...
CALL FUNCTION 'CO_FS_SORT_COMPONENT_LIKE_BOM' "
TABLES
sort_tab = i_sort.
...
" transfer i_sort contents back to your reports internal table.
... .