VMware vSphere products are available for free evaluation and come with a 60 days trial period, which should be enough for most but you may be caught at some point in a situation where you need to have a bit more time to try things out.
Please note that this method isn’t approved or supported by VMware and should not be used to use the product for free, and not to mention it, this isn’t a recommended approach for any production environment. This approach works with a standalone host and most likely won’t work if the host is attached to a vCenter. If you like and use the software, please get a proper license.
1. Login to the hypervisor using SSH (service has to be started first) ;
2. Remove the current license :
rm -r /etc/vmware/license.cfg
3. Copy the source evaluation license (already on the host) with the same name as the precious license :
cp /etc/vmware/.#license.cfg /etc/vmware/license.cfg
4. Restart the vpxa service to make it effective :
/etc/init.d/vpxa restart
You now should see the evaluation period back to 60 days.