How to invoke product rules outside the configurator

Hello Experts,

One of my customer is having following requirement:

Customer would like to invoke the product rules outside the configurator like on the click of a button in the line items view.

For that they have designed a workflow that invokes and executes the product rules and constraints.

The Business service that they use to do the validation in this workflow is - 'Complex Object Instance Service' and the method they call is – 'BatchValidate'.

So requirement is , when the output argument “batch validation status” is set to incomplete. In such a scenario they would like to display the message that gets generated when the validation fails.