Not necessarily a pure Cisco post , but most engineers will encounter some ESX/VMWare work every now and then. so let me spit out some basics.
Open your host and got to the "Configuration" tab, the choose Add Networking (see below)
This will give you a summary of the already existing vSwitches and the vmnics that belong to it
Lets say, I wanted my management to the host to use different vmnic's then the existing virtual machines on the host.
After selecting Add Networking, you get the choice to either create a new Virtual machine or a VM Kernel (see below)
so the next screen will summarize which vmnics you have available, in our case only vmnic3 as vmnics 0, 1 and 2 are already assigned to vSwitch0 (with vmnic2 being down).
So tick the vmnics that need to be added to the new vSwitch.
Next screen will allow you to add a VLAN to it, and a label.
Next, you will be asked to add and IP address, to the Kernel, I am leaving that as it is and choose, Obtain IP settings automatically. As I will move the management over from vSwitch0 to this newly created vSwitch1 later.
OK, so I just removed the vmnic2 off the vSwitch0, let me show you how to add it back into the newly created vSwitch1. You should now have something similar to the screen shot below, or at least a summary that contains your newly created vSwitch1, with a single vmnic3 as part of that.
OK, so go to properties on your vSwitch1, then to the Network Adapters tab.
As you see, only vmnic3 is part of the vSwitch1, but then we already knew that, so click ADD. and select vnmic2.
click NEXT a couple of times et voila!