how to change Xorg display from :0 to :1

[cssidhu]

This is my system information, currently installed Centos 6.3 :

uname -a

Linux mylocalhost 2.6.32-279.el6.x86_64 #1 SMP Fri Jun 22 12:19:21 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

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Issue:

Now on my present centos 6.3 install my /usr/bin/Xorg:0 is process is running on display :0 on tty1 as seen below :

ps -ef | grep Xorg

root 2174 1 0 11:54 tty7 00:00:01 Xorg vt7 -query remotehostname :1.0
root 2220 2218 0 11:54 tty1 00:00:11 /usr/bin/Xorg :0 -nr -verbose -audit 4 -auth /var/run/gdm/auth-for-gdm-WnUXzz/database vt1
root 3321 2810 0 13:48 pts/0 00:00:00 grep Xorg

Before I migrated from Centos 6.2 to Centos 6.3, /usr/bin/Xorg:1 was running on display :1 on tty7 as seen below :

root 2219 2217 0 11:05 tty7 00:00:07 /usr/bin/Xorg :1 -br -verbose -auth /var/run/gdm/auth-for-gdm-iaSbcA/database -nolisten tcp

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Question

Now is there a way I can have the process "root 2220 2218 0 11:54 tty1 00:00:11 /usr/bin/Xorg :0 -nr -verbose -audit 4 -auth /var/run/gdm/auth-for-gdm-WnUXzz/database vt1" changed to "root 2219 2217 0 11:05 tty7 00:00:07 /usr/bin/Xorg :1 -br -verbose -auth /var/run/gdm/auth-for-gdm-iaSbcA/database -nolisten tcp".

I am unable to find the file where i can make this specific change to fix this issue and I've been trying to work gdm custom.conf in centos 6.3 but it doesn't have any impact.

If their is anyone who can put me in the right direction i'll be very grateful, i hope i've made my question clear.