Delete Condition record using BAPI_SALESORDER_CHANGE

I am unable to delete a condition record using BAPI_Salesorder_change though I have put the updateflag as D.

I have the following code.

y_lv_kbetr = ( y_wa_konv1-kbetr / 10 ).

move y_k_d to y_wa_condx-updateflag.

*delete condition type, if added

move: y_k_x to y_v_change,

y_lv_kbetr to y_wa_cond-cond_value,

y_k_x to y_wa_condx-cond_value,

y_wa_konv1-kposn to y_wa_cond-itm_number,

y_wa_konv1-stunr to y_wa_cond-cond_st_no,

y_wa_konv1-zaehk to y_wa_cond-cond_count,

y_wa_konv1-kposn to y_wa_condx-itm_number,

y_wa_konv1-stunr to y_wa_condx-cond_st_no,

y_wa_konv1-zaehk to y_wa_condx-cond_count,

y_wa_konv1-kschl to y_wa_condx-cond_type,

y_wa_konv1-kschl to y_wa_cond-cond_type.

append y_wa_cond to y_i_cond.

append y_wa_condx to y_i_condx.

Could you tell me what is wrong? it updates with update flag U but does not delete.