If you made some changes in httpd.conf file you probable notice that all your changes are removed after a while, anyway the time to be removed can vary 2-3 weeks. In the following I will show you how to change the httpd.conf file without lose your modifications.
If you open up the httpd.conf look in the VirtualHost you need to change settings for a comment which should look like this:
# To customize this VirtualHost use an include file at the following location
Now just copy the path where you should create the file and run the following command (you need root access, to access httpd.conf file).
mkdir -p your_path/domain.com/
The above command will create a folder with the name domain.com, now, we need to create the conf file and in this file you would be able to add all modifications you need and them won't be removed. To create the file run the following command:
This will open the file, add your settings and save file. The final steps are to restart the apache server, this can be done running the following command:
service httpd restart
Now you have to run the last command, the last one will recreate the httpd.conf file for you.
That's it. Now all your modifications for a certain virtual host should remain as they are. If you have any questios use the comments section and I will try to help you.