Hi,
If you are new to this, I *strongly* advise not to change fop2 listening port. If you want to test it out temporarely, you can just stop FOP1 while you test FOP2, without modifying either configuration files:
/usr/sbin/amportal stop_fop
(at that point fop1 server is not running, port 4445 is available to be used by fop2).
service fop2 start
(now you have fop2 running, try it, log into fop2 with your browser.. see if you like it or not).
Now, if you want to restart fop1:
service fop2 stop
/usr/sbin/amportal start_fop
And to remove fop2 from starting every boot:
chkconfig fop2 off
Changing ports in fop2 is not complicated, but you *will* face issues that will be hard to troulbeshot by newbies and experienced sysadmins alike.