Delete User Quota

Please, can somebody tell me how can I delete a user quota from Unisphere or UEMCLI, SVC, API, Powershell?

There is no DELETE button or options in user quota page in UNISPHERE UNITY  GUI or from UEMCLI there is no a REMOVE or DELETE option.

I put the hard quota limit and soft limit to ZERO, all good, but the entry is still there.

any advised?

thanks.