Assigning Values To Multiple Variables (via Subqueries) For Use In An Update

Hi, figured out where I was going wrong in my post just prior, but is
there ANY way I can assign several variables to then use them in an
Update statement, for example (this does not work):

ALTER PROCEDURE dbo.UpdateXmlWF
(
@varWO varchar(50)
)
AS
DECLARE @varCust VARCHAR(50)
SELECT @varCust = (SELECT Customer FROM tblWorkOrders
WHERE WorkOrder=@varWO)

DECLARE @varAssy VARCHAR(50)
SELECT @varAssy=(SELECT Assy FROM tblWorkOrders
WHERE WorkOrder=@varWO)

UPDATE statement here using declared variables...

I can set one @variable but not multiple. Any clues? kinda new to
this.

Thanks,
Kathy