on update catch 22

How do you make an update cascade opperation if you want to set the PK to an excisting one?
I have a table where to post are the same only the PK differs, now I want to delete one but transfer it's dependecies. i.e redirect its references to the other post.
How can I do that using on update cascade/delete. I see a catch 22 coming up!

/Jonneponne

Hi

I would redirect all dependencies to a single post you want to keep and then delete a duplicate post.

ON UPDATE CASCADE works only if you are trying to update the KEY references by Foreign Key , not the other way round.

NB.