change run level
 

There is a linux server, many of user's are working on the server, at the time I would like to change the run level (3 to 5) without affecting that working user's ...
can anyone say how to accomblish this process in server....

Edit the /etc/inittab and upon next reboot, should startup in 5.

You can also to a telinit 5 from the command line.

man telinit for more details.