>I have what I think should be a simple problem, but I don't see a solution. It's sort of like I want to
>

SET RELATION TO bla-bla IM MyTable INTO MyTable

>
>which of course makes no sense.

You can always open your table twice - that's the purpose of the AGAIN... ALIAS clauses in the USE command. That way your table develops a double personality (i.e. double set of buffers), and you can relate it to itself any way you like, provided you got proper index tags in place.

use mytable
use mytable again alias myTableAlterEgo in 0 order YourFavoriteTag
SET RELATION TO bla-bla-duh in MyTable INTO myTableAlterEgo