I have been searching the web for a solution to this issue with no luck. I have a team project in Visual Studio Team Services (VSTS) using an inherited copy of the scrum proces
While in TFS you can use witadmin.exe (or the old API) to update work items, this does not with VSTS.
If you are on the inherited template model then your only option is to use the Web Interface to edit the work items. There is some API's for working with this in the new Rest API's: https://www.visualstudio.com/en-us/docs/integrate/api/overview