Sathishvija,
Are the VM's using shared storage? Do they reside on local storage in the ESXi host? Are you using VDS? Or a local vswitch? Do you have VLANS? Are you keeping the VM's on that ESXi host when you move it to the new vCenter server? Or are you moving the VM's to a new Datacenter on the existing vCenter server? There are lots of things that can affect how you make this change.
Based on the little information you provided about your infrastructure I will take a guess. I'll assume everything is on the same physical network and network segment. And I'm assuming that you are using local storage or shared storage that is presented to the new cluster you are moving the ESXi host to. It sounds like you want to move the VM's to the new vCenter you are moving the ESXi host to. If that is the case then it's a simple remove the ESXi host from the current vCenter then add the host to the new vCenter server. If you are using VDS then you need to make sure all the networking your VM's are using is replicated to the new vCenter. Also If you are using VDS you should create a local vswitch on the ESXi host with the network your VM's are using. Then change the networking in the guest VM nic to use the local vswitch you created. This way your VM's won't lose any network connectivity when you remove the ESXi host from vCenter. Once you remove the ESXi host from the current vCenter you can add it to the new vCenter server then you change your guest VM nic's to use the appropriate VDS port groups. If you are using a local vswitch and not VDS then you won't have to worry about any of the VDS stuff.
It's a bit difficult to give you specific steps when I have no information regarding your current setup. I hope this is helpful to you.