• I have found a solution

    update c

    set [Description] =

    Replace([Description], [Description] ,(t.accountid + ' - ' + [Description]) )

    FROM [Document].[dbo].[DOC.Client] as c

    inner join [Reporting].[dbo].[Tran] as t

    on t.Id = c.accountindex

    :-):-):-):-):-)