Update the details of a Web Enrolment. 

A Client or Employer Web Enrolment must have previously been created, see AddClientWebEnrolment or AddEmployerWebEnrolment. This function updates the description and reason for study for the given Web Enrolment. 

A Web Enrolment ID (webEnrolId) is passed as a parameter. This should be the ID returned by the AddClientWebEnrolment or AddEmployerWebEnrolment function. 

A token is passed for authentication. If the authentication fails, or other errors occur, nothing is updated . The result of the authentication is represented by a TAuthenticate object. 

The only mandatory parameters are token and webEnrolId. An empty string can be passed for the description, and null or 0 for the studyReasonId. 

Requires a valid registration key entry for the Short Courses feature. 

This function has security level "Protected", and can only be accessed by users that have explicitly been granted permission to the API.

[WebMethod(Description = "Updates the details of the specified web enrolment ID")]
public TAuthenticate UpdateWebEnrolment(string token, int webEnrolId, string description, int? studyReasonId);