Is there any way to call AlertDefinition from formatcontrol or Process

When does AlertDef gets called? Is there any way to call AlertDef from formatcontrol or Process

 

Or Is is possible to create scheduler and call alertDefinition

Our requirement is :- For a line item there is a target completion date  is set based on custom fields and which it should fire an alert notification once it exceeds the target date. Any solutions to achieve this?