ALTER Table Primary Key

If a primary key already doesn't already exists. then you want to do this

ALTER TABLE provider ADD PRIMARY KEY(person,place,thing);

If a primary key already exists then you want to do this

drop primary key
ALTER TABLE Table1DROP CONSTRAINT PK_Table1_Col1GO


ALTER TABLE [dbo].[tbl_Excel_Tier1Tier2IDs]
   drop constraint [PK_tbl_Excel_Tier1Tier2IDs]
GO


 ALTER TABLE [dbo].[tbl_Excel_Tier1Tier2IDs]
   ADD PRIMARY KEY(Agent_Name, PwC_GUID, Effective_Date);


ALTER TABLE dbo.tblComment_Review
ADD FOREIGN KEY (Record_ID)
REFERENCES [dbo].[tblSurvey_Response_2](Record_ID)