changing the "hi galaxy" phrase. is it even possible? Every once in a while, my note 3 wakes up on its own thinking somebody said "Hi Galaxy" and gets itself into the listening mode to start capturing what it hears from that moment on, then submits to Google for a search! 

Boy! I had a few situations and eventually I had to turn off that awesome feature. 

Is there a way to change this "hi galaxy" phrase to something less likely to be confused?
Can I personalize it? 

Something like "ok Samsung, wake up now!" or "ok note 3, wake up now" etc...
the longer the phrase, the less likelyhood for an unintentional match, I assume. 

Also, being able to personalize this phrase will prevent other people's getting your way... Imagine, the guy in the bus says "Hi galaxy" to his phone and all the galaxy devices in the bus within reach wakes up. LOL!
Open the S Voice app, and open its settings. You should be able to change it via Set wake-up command.

Here's the setting from my Samsung Galaxy S4: