I have a field called tblPeople. It has an AutoNumber field as its PK, it has
a field called ID which is a text field, indexed (no dupes).

I have another table called tblEvents. In tblEvents I have amongst others,
two fields, Manager and Director. I am trying to create relationships between
tblEvents.Manager and tblPeople.ID, and also between tblEvents.Director and
tblPeople.ID. I have done that.

What I can't do though, is set Referential Integrity with Cascading Updates
so that if a person's ID changes (which it can, since it is an ID Badge
Number) it updates the records in tblEvents.

Any ideas?