Verified in CFME 5.7.2.0 (5.7.2.0.20170321181409_349f1b1) in Chrome, against vSphere providers.
The retirement options in the Lifecycle button are enabled for retired (non-archived/orphaned) infrastructure VMs from their details page. I was able to set a future retirement date via the Lifecycle 'Set Retirement Date' button, resuming the retired VM.
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