Automating Assigned To Attribute

We have a Custom Attribute called "Assigned To".  Currently this is used in several Smart Responses for when you set an Incident to In Progress or Some other Status.  As it is currently configured, you have to manually enter a value when you change the status of the Incident.  We use {UID} as a place holder in the Smart Response (See attached picture UID.jpg)

My question is, is there a way to automate this so that when someone chooses the Smart Response, it automatically populates the "Assigned To" field with their user ID or name?