EXEC sp_addlinkedserver @server='CRM',
                        @srvproduct='',
                        @provider='SQLNCLI',
                        @datasrc='<IP of CRM>'

EXEC sp_addlinkedsrvlogin
                        @useself='FALSE',
                        @rmtsrvname='CRM',
                        @rmtuser='<username>',
                        @rmtpassword='<userpassword>'

UPDATE [CRM].DB.dbo.table1
SET field = 1
WHERE id = (SELECT id FROM [CRM].DB.dbo.table2 WHERE secondary_id = 9999)

CREATE PROCEDURE UPD_CRM_TableName(
    @ID int,
    @Field int)

UPDATE TableName SET
@Field = Field

WHERE @ID = ID