Not directly. PPRO provides backward compatibility--the ability to load projects from older versions in newer versions. However, it is not forward compatible--you can't open projects from a newer version in an older version.
But what you can do is export the project as FCP XML (or AAF) file: File>Export>FCP XML. Then you'll be able to import the xml file into CS6. Be aware, though, that some details may be lost in translation, particularly any effects or transitions that were new to CC.
What version is the trial? If it is older than CS6, then yes, as Mark pointed out, old project files open in newer software. Just not the other way around.
Ah, I misread the post: "The trial version is an earlier version than CS6." If that's the case, then the project should open in CS6.