To change the SSH port number login as root and edit /etc/ssh/sshd_config

Find the line that says Port 22 and change 22 to any number between 1024->65535 (above 30000 is best) and save the file

Once done run

/etc/init.d/sshd restart

Now start a new SSH session (don't close your existing one) to make sure that you can get in. If that is ok you can now login on that port. If not change it back. If you get locked out ask support to fix it for you