private void UpdateContacts(EntityCollection contacts, Entity contact)
        {
            if (contacts == null)
            {
                return;
            }
            if (contact == null)
            {
                return;
            }
            ExecuteTransactionRequest multipleRequest = new ExecuteTransactionRequest {
                Requests        = new OrganizationRequestCollection(),
                ReturnResponses = true
            };

            foreach (Entity existingContact in contacts.Entities)
            {
                contact[Attributes.Contact.ContactId] = existingContact.Id;
                var updateRequest = new UpdateRequest {
                    Target = contact
                };
                multipleRequest.Requests.Add(updateRequest);
                if (multipleRequest.Requests.Count == 500)
                {
                    payloadCustomer.Response = CommonXrm.BulkUpdate(multipleRequest, crmService);
                    multipleRequest.Requests.Clear();
                }
            }
            if (multipleRequest.Requests.Count > 0)
            {
                payloadCustomer.Response = CommonXrm.BulkUpdate(multipleRequest, crmService);
            }
        }