>Guess I should have tried that, but the docs clearly say this is for one to many relationships. Thanks.

Hmm. Further examination of the ALTER TABLE docs, and a test program later,
I did this:

CLOSE DATABASES ALL
CLOSE TABLES ALL
create database c:\crap\test
open database c:\crap\test

CREATE TABLE MyTable1 (id  I PRIMARY KEY, name C(10))

CREATE TABLE MyTable2 (id  I  PRIMARY KEY, othername C(10))

USE MyTable2 excl

ALTER TABLE MyTable2 ALTER COLUMN id I PRIMARY KEY REFERENCES MyTable1 

CLOSE DATABASES ALL
CLOSE TABLES ALL