how to upgrade from i386-9.0 to amd64/9.x

Tue Jan 28 16:32:30 UTC 2014

Hi, I am currently running the following i386 9.0 on my firewall system.

FreeBSD jessie.mcd.on.ca 9.0-RELEASE FreeBSD 9.0-RELEASE #0: Tue Jan  3 07:15:25 UTC 2012     root at obrian.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386

I need to upgrade to 9.1 or 9.2 or higher but I'd also like to switch over to amd64 as 
my install of i386 was a stupid mistake 2 years ago :-).

tips on how to install /upgrade please?   Will the installer of amd64/9.2 notice my existing system?

thanks,
doug