Linq2SQL: Update object not created in datacontext

public static void Save(Client client)
    {
        CompanyDataContext db = new CompanyDataContext();
        Validate(client);
        if(client.Id.Equals(Guid.Empty))
        {
            //Create (right?):
            client.Id = Guid.NewGuid();
            db.Clients.InsertOnSubmit(client);
            db.SubmitChanges();
        }
        else
        {
            //Update:
            OffertaDataContext db = new OffertaDataContext();
            db.Clients.????

        }
    }

ctx.Customers.Attach(customer); // optional bool to treat as modified

public override IEnumerable(memberState) GetMembersByState(string @state)<br/>
{<br/>
using (BulletinWizardDataContext context = DataContext)<br/>
{<br/>
IEnumerable(memberState) mems = (from m in context.Members<br/>
join ma in context.MemberAddresses<br/>
on m.UserId equals ma.UserId<br/>
join s in context.States<br/>
on ma.StateId equals s.StateId<br/>
where s.StateName == @state<br/>
select new memberState<br/>
{<br/>
userId = m.UserID,<br/>
firstName = m.FirstName,<br/>
middleInitial = m.MiddleInitial,<br/>
lastName = m.LastName,<br/>
createDate = m.CreateDate,<br/>
modifyDate = m.ModifyDate<br/>
}).ToArray(memberState)();<br/>
return mems;
}
}