How to set-culture for UseUserOverride

When I execute get culture command I am getting the below information

PS C:\> get-culture | Format-List -Property *


Parent                         : en
LCID                           : 4105
KeyboardLayoutId               : 4105
Name                           : en-CA
:
UseUserOverride                : True
IsReadOnly                     : False

I want to change UseUserOverride to false because our third party application is doing C# Date to string conversion Date.Value.ToString(String Format), Not passing the culture. We cannot change the third party application to include culture invariant.

Any help is appreciated.