Just Invoke this Function, Wherever you need to change the ASP.NET_Session ID
Sub RegenerateID()
Dim manager
Dim oldId As String
Dim newId As String
Dim isRedir As Boolean
Dim isAdd As Boolean
Dim ctx As HttpApplication
Dim mods As HttpModuleCollection
Dim ssm As System.Web.SessionState.SessionStateModule
Dim fields() As System.Reflection.FieldInfo
Dim rqIdField As System.Reflection.FieldInfo
Dim rqLockIdField As System.Reflection.FieldInfo
Dim rqStateNotFoundField As System.Reflection.FieldInfo
Dim _nbrqPath As System.Reflection.FieldInfo
Dim store As SessionStateStoreProviderBase
Dim field As System.Reflection.FieldInfo
Dim lockId
manager = New System.Web.SessionState.SessionIDManager
oldId = manager.GetSessionID(Context)
newId = manager.CreateSessionID(Context)
manager.SaveSessionID(Context, newId, isRedir, isAdd)
ctx = HttpContext.Current.ApplicationInstance
mods = ctx.Modules
ssm = CType(mods.Get("Session"), System.Web.SessionState.SessionStateModule)
fields = ssm.GetType.GetFields(System.Reflection.BindingFlags.NonPublic Or System.Reflection.BindingFlags.Instance)
store = Nothing : rqLockIdField = Nothing : rqIdField = Nothing : rqStateNotFoundField = Nothing : _nbrqPath = Nothing
For Each field In fields
If (field.Name.Equals("_store")) Then store = CType(field.GetValue(ssm), SessionStateStoreProviderBase)
If (field.Name.Equals("_rqId")) Then rqIdField = field
If (field.Name.Equals("_rqLockId")) Then rqLockIdField = field
If (field.Name.Equals("_rqSessionStateNotFound")) Then rqStateNotFoundField = field
Next
lockId = rqLockIdField.GetValue(ssm)
If ((Not IsNothing(lockId)) And (Not IsNothing(oldId))) Then store.ReleaseItemExclusive(Context, oldId, lockId)
rqStateNotFoundField.SetValue(ssm, True)
rqIdField.SetValue(ssm, newId)
End Sub