Verified on CFME-5.7.2/RHV-4.0.5: VM Reconfigure: cpu sockets 4->1, memory 100M->256M CFME request succeed. On RHV side, VM memory updated to 356 MB (as expected, memory delta is rounded to 256MB), and CPU hot unplug failed on: "Hot un-plugging a CPU is not supported for cluster version 4.0 and architecture x86_64." As this bug do not handle the cpu hot unplug, and it will documented, moving bug to verified.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2017:0898