Licensing for RHEL

I wanted to know about licensing for RHEL. We have 3 RHELs as virtual machines using Vmware in our company. A 4th instance is required now but there is talk of not having the 4th license as we have only 3 licenses. Apart from this , I wanted to know how to actually practically enable a license for RHEL installed on a base machine or a virtual machine.

I hope, my question is clear.

Please revert with the reply to my query.

Regards

See Red Hat License Agreements

Thanks for your answer.