How to configure an approval workflow basing on a custom employment Action

Summary:

How to configure an approval workflow basing on a custom employment Action

Content (please ensure you mask any confidential information):

Hi,

we would like to configure an approval workflow. The trigger that allows to start the workflow is a particular action to update the employee assignment (the action is not a seeded one but it's a custom one). Then when I update the employee assignment, selecting the aforementioned Action, the approval workflow has to be started.
Hoping someone has some suggestions.

Thanks a lot,

Alberto.

Version (include the version you are using, if applicable):

24 A

Code Snippet (add any code snippets that support your topic, if applicable):