How to run a workflow based on date field in Subform?

How to run a workflow based on date field in Subform?

Hello, 

in the "Invoices" module I have added a subform that contains several fields incl. a date field. I am running a workflow and several lines/records in this subform will be created. 

And I want to run another workflow based on the date field in the last row in this subform (please see screenshot) PLUS I need to update the field "Subscriptions_Status" (picklist) to the value "Cancelled". 



How can I do this? 

Thanks, Michael