Hi Naveen,
Just put a module in PBO, in this module try below code:
module check_value.
if lv_value eq 'Billable' and lv_notes is initial.
message e001(00) with 'Enter a value'.
elseif lv_value eq 'Non-Billable' and lv_RD is initial.
message e.....
endif.
endmodule
regards,
Archer