Automate Conversion of Negative Invoice Lines - Salesforce Billing

Issue :

1. If you want to convert a Negative Invoice(with Negative Invoice Lines), you would have to hit the button on the Invoice called "Convert Negative Lines" to create the Credit Note from Invoice
2. If you want to have a few invoices then it's very easy to convert them manually, what if
1. You have hundreds of Invoices?
2. You want to automate the process of credit note creation from Negative Invoice Lines?
3. You don't want Finance Users to convert manually?

Solution :

1. The answer to all the above questions is, Salesforce Billing now provides Rest API & apex class to automate the process of Negative Invoice Lines to Credit Notes. Thanks to Spring ’20
1. Use Apex Class blng__NegativeInvoiceToCreditNoteAction if you want to call from the Salesforce org
2. Use Rest API to make an inbound call to Salesforce from the external system.  
2. The advantages are you can automate this process and you can convert multiple Negative Invoices to Credit Notes in one transaction.  

How do you call the Apex class blng__NegativeInvoiceToCreditNoteAction using the Process Builder : 

1. Create the field on the Invoice like "Converted Invoice into Credit Note?" as default value as false. This will ensure the process builder will execute only once.
2. Create the Process Builder and select the action Call Apex. Entry criteria for the Process Builder depend upon the business and when you want to automate/create the Credit Note. 

Common Issues/Troubleshooting :

1. Before you make a call to the above class, make sure the Invoice is Posted. If you try to call the apex class on Draft Invoice or Cancelled Invoice you will get an error. 
2. Add the apex class blng__negativeinvoicetocreditnoteaction to profiles if you want to use this in the Process Builder

In Conclusion : 

1. Use the apex class blng__NegativeInvoiceToCreditNoteAction or rest API to automate the process without any manual step or customization.
2. Please note Billing will only create the Credit Note and Credit Lines. But Credit Note is not allocated to Invoice. You would have to do manually allocate to any invoice. Hope Salesforce Billing will give a new API/Class to automate in the future.

Related Posts : 

1. Salesforce Release Notes for Conversion of Negative Invoice Lines