You can change option in third line in /etc/hosts file on Linux server without rebooting;
/etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.0.1 server.computeman.com computeman
You can change all of the following options in /etc/sysconfig/network without reboot.
/etc/sysconfig/network
NETWORKING=yes
HOSTNAME=server.computeman.com
GATEWAY=192.168.0.1
Similarly options in /etc/sysconfig/network-scripts/ifcfg-eth0 can also be changed.
/etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.1
NETMASK=255.255.255.0
Hostname of server can be changed with;
hostname server.computeman.com
Restart network with;
systemctl restart network