Alter table column constraint

[Rich Shepard <rshepard@xxxxxxxxxxxxxxx>]

  I want to alter a term in a column's constraint to allow only specified
strings as attributes and have not found how to do this in the docs (using
version 10 docs now). There is an alter table command that allows renaming a
constraint but I've not seen how to modify the constraint itself.

  Pointer to a reference needed.

TIA,

Rich