RegenerateRelation() api not updating relation value in model

I am using Creo Parametric 2.0 M250

Requirement is to modify relation value in creo using Vb api
I am using RegenerateRelation ()api its giving following error
pfcExceptions::XToolkitGeneralError
at pfcls.IpfcRelationOwner.RegenerateRelations()
at customApp.modInit.changeDateFromRelation(IpfcModel iObjModel, String strToProcess)



Here are the errors that I faced
pfcExceptions::XToolkitGeneralError
at pfcls.IpfcRelationOwner.RegenerateRelations()
at customApp.modInit.changeDateFromRelation(IpfcModel iObjModel, String strToProcess)