Selected lines now how do I update?

Hi,

I'm having a problem getting an UPDATE right after having selected the records to update.

Here's my select :

WITH T AS (

SELECT
NewCLIENT, OldCLIENT,
FROM MyTable1 WHERE etc, etc )

SELECT * FROM MyRefTable JOIN T ON
MyRefclient=OldCLIENT




Now I want to replace the old client with the new, but this doesn't seem to be right :

UPDATE MyRefTable
SET OldCLIENT = NewCLIENT WHERE OldClient in (

WITH T AS (

SELECT
NewCLIENT, OldCLIENT,
FROM MyTable1 WHERE etc, etc )

SELECT * FROM MyRefTable JOIN T ON
MyRefclient=OldCLIENT )


Thanks for any help.