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.