Notification on conversion of Pending Worker to Employee

Summary

A notification/alert needs to be triggered to a specific user when a pending worker is converted to an employee

Content

The requirement is such that a specific user needs to receive a notification/alert when a pending worker is converted to an employee? Alert Composer can be used for the same but what should be the EL expression for this condition? Or is there any document on how to write EL expressions in Alert Composer? 

Any guidance is highly appreciated.

Version

20D