Workflow not triggered with ISR_NOTIFICATION_CHANGE

Dear experts,

I am creating a workflow by calling FM  ISR_NOTIFICATION_CREATE. This triggers my workflow.

Later I make some updates to the ISR notification using  ISR_NOTIFICATION_CHANGE. But during this, the workflow is not triggered.

I have the CREATED, DATACHANGED and INPROCESSAGAIN events active for business object BUS7051.

I am not sure what is missing, but the  ISR_NOTIFICATION_CHANGE is not triggering workflow. Please help.

Thanks,

Shalini