Cantact dialer

Hey guy, I hope I'm in the right forum here. I FINALLY got myself a NOTE 4 and I love it. But something caught my eye the other day. My fiancé has a Note as well (AT&T) and whenever she gets a call; she can put her call on hold and then go back to it when she's done. It's like she gets an extra step that we don’t on our phone. I was wondering if anyone had ever tried porting a stock TouchWiz contact dialer from an AT&T/T-Mobile Note 4 over to a Sprint Note 4? Again sorry if this seems like a dumb question, but that little detail seemed kool to me and even though I searched for it, I couldn't find a dialer apk files anywhere. Then again, I don't know if it's even possible. Any help/guidance would be much appreciated, Thanx.