SPFX Webpart - Page Property refresh event

I'm working on a SPFX Webpart that accesses the Page Properties of a Modern Page.
Is there a way to be notfied in Page Edit mode when a user modifies a Page Property.

For example:

The users selects a different value from a dropdown list in Page edit mode and my webparts needs to be notfied that the property has changed to access the new value. 

The page properties webpart correctly refreshes, but i couldn't figure out, how this works.