Hi Thiru,
If my understanding is right, please use the below piece of code for your requirement.
{Whenever the status is been changed, the values in your user fields (ABC,XYZ) should be cleared, I mean they should be null & you can select the required from the drop down list.....THIS IS MY UNDERSTANDING}
Select Case TestSetTest_Fields("TS_STATUS").Value
Case "New"
TestSetTest_Fields.Field("TS_USER_21").Value =""
Case "Closed"
TestSetTest_Fields.Field("TS_USER_21").Value =""
End Select
When ever the status is been changed, the values in those field will be cleared off.
Thanks
Damodar