How to create "Prolongate" request for PWO from script?

Question

I'm trying to create "Prolongate" request for PWO via script. 
 It should be as simple as 
 Dim obj As ISingleDbObject = Connection.CreateSingle("PersonWantsOrg", <UID_ PersonWantsOrg >) Dim res As Object = obj.Custom.CallMethod("Prolongate", DateAdd("d", 123, Now.Date()) ) 
 but it does not work. Exception is not thrown, but "res" variable is null and renewal process is not created. 
 
 I tried to run this script from Designer, Object Browser, process. No luck. 
 If I run "Prolongate" method for the same PWO in Object Browser, new renewal process is created.

We are using 8.0

Markus Weiss-Ehlers · Answer

You should use the following code (based on the script samples 11 Call database object methods.vb from the SDK that comes with OneIM). The key is to save the object after calling the method. 
 
 Dim dbPersonWantsOrg As IEntity 
 ' Load the PersonWantsOrg object dbPersonWantsOrg = Session.Source.Get("PersonWantsOrg", "uidPersonWantsOrg") 
 Try 
 ' Call customizer method Prolongate dbPersonWantsOrg.CallMethod("Prolongate", DateAdd("d", 123, Now.Date())) ' Save to execute the method dbPersonWantsOrg.Save(Session) 
 Catch ex As Exception ' Error handling VID_Write2Log("C:\Test.log", ViException.ErrorString(ex)) 
 End Try

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How to create "Prolongate" request for PWO from script?