I recently came across an issue that required PTagent to be removed from a couple of Dell XC Nutanix nodes. Thankfully, the removal is fairly straight forward. Connect to your ESX shell and run the following command.

[root@esx:~] esxcli software vib remove -n dellptagent

Removal Result
   Message: Operation finished successfully.
   Reboot Required: false
   VIBs Installed:
   VIBs Removed: Dell_bootbank_dellptagent_1.8.1-19
   VIBs Skipped:

More documentation can be found on the Nutanix support portal here.