Trigger PI outbound Interface upon BKPF table update

Hi Experts,

Currently in our SAP R/3 4.7, a scheduled Z-program updates field 'XBLNR' in BKPF table using BAPI 'CHANGE_DOCUMENT' based upon file contents read from application directory 'AL11'.

After every update for 'XBLNR' in BKPF table, I want to trigger something(RFC, event, method, etc.) in SAP R/3 4.7, which will trigger SAP PI outbound interface to send data update to 3rd party system.

How can we trigger/capture this to call an outbound PI interface? How we can achieve this?

Thanks,

Amit Patil