How do I change my vm display from Spice server to VNC server on KVM? (virt-manager)

I have several KVM virtual machines on a server (runs Ubuntu Server 16.10) hosted in another part of town. I access them using ssh on my laptop (Running Ubuntu Desktop 16.10) using virt-manager and the terminal. On one of the VMs I made the mistake of not changing the display setting from Spice server to VNC server. Now I am experiencing an issue where if I don't change the display setting from Spice sever to Display Server, I encounter a never-ending password-prompt loop. I have encountered this bug before. And the only way that I could fix it was to delete the VM and and start from scratch. This is not acceptable and I can't afford to do that. I know that virt-manager does not have a VM setting GUI like VMware or virtual box, instead you have to change system files. I have googled on which ones I have to changed and nothing has helped me. I need to know how to change the display setting to VNC server. Any help will be greatly appreciated for I am desperate to find an answer as soon as possible.

Thanks,

fromwin2lin