Dear Balaji,
I found the solution and its working fine .
CALL METHOD cl_mdg_bs_bp_fru=>get_instance
EXPORTING
iv_model_name = 'BP'
iv_classname = 'CL_USMD_CONV_SOM_GOV_API'
RECEIVING
ro_so_gov_api = lo_mo_conv1.
lv_note_created = lo_mo_conv1->mv_note_created
and check ur button action in lo_mo_conv1->mv_crequest_action
and if ur reject button action is called or pressed on UI then and mv_note_created is initial then show error message..
Above code you need to write in CHECK_ENTITY BADI.
Thanks
Sachin Kapoor