Change the default apache port

[Bkmz]

Hi. I'm newbie in cPanel. I need to change the default port of Apache's VirtualHosts. So, I going to tweak settings, change there default value to 0.0.0.0:81. After that I execute following commands:

/usr/local/cpanel/whostmgr/bin/whostmgr2 --updatetweaksettings
/usr/local/cpanel/bin/apache_conf_distiller --update
/scripts/rebuildhttpdconf

And the last command exiting with following error:

This tool unavailable until Apache is built by EasyApache 3.x at ./buildhttpdconf line 42.

How can i rebuild the httpd.conf?
PS i can use sed, but it's not cPanel way, as i understand

[Infopro]

Is Apache up and running already?

[cPanelMichael]

Hello

This tool unavailable until Apache is built by EasyApache 3.x at ./buildhttpdconf line 42.

This message typically indicates Apache has been installed via your system package manager rather than via EasyApache.

Could you post the output of the following command:

# /usr/sbin/httpd -v

Thank you.