FRM-40200 error when I tried to change value set validation type from none to table

  Hi there,

 

I just wonder if I can get some help on DFF value set setup.

 

Situation:

1)       Value set is Oracle seeded: FV_6_CHARS

2)       It is used and only used by 3 DFFs

3)       We like to change it to use values from a column in an Oracle seeded table

 

What I have tried so far:

 

A)     unfroze 3 DFFs

      current validation type = none.  When I tried to change it to table, I got error: FRM-40200 field is protected against update

 

Please advise how I can get ride of the error and move on?

 

Thanks,

Ning