Well I would say to just build your new ePO environment on the physical machine, and then migrate everything from the old > new; but running 4.5.6 doesn't allow you to do certain import/export things as 4.6+ does.
Basically you could at a high level:
1. build your new ePO
2. add the new ePO as a registered server in the old, share the security keys
3. export from old your policies/tags/tree/queries/etc and import it into the new
4. migrate machines from old > new
5. configure the rest as needed
Thanks alot for the reply,
I have more than 1500 computers connected to this ePO server and i am not using default port numbers, I am using 9081,9443,9444,90
will it be any issue, will epo allow me to change ports during the installation as i have not seen the ePO5.1 setup.
I migrated over 10k+ machines recently; built a new ePO server and then slowly migrated everything as noted.
If you go to Menu > Configuration > Server Settings > Ports, you can setup the ports for communication.