> ## Documentation Index
> Fetch the complete documentation index at: https://docs.superoffice.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How to link a sale to a follow-up (services)

> How to link a sale to a follow-up using web services.

This section shows how we can add a link using the NetServer Services layer. The link to a related sale appears in the **Links** tab of the **Follow-up** dialog.

![Links tab of the Follow-up dialog -screenshot][img1]

## Code

In this example, we use the `AppointmentAgent` to retrieve an `AppointmentEntity`. Then we relate the follow-up to a sale using its `Links` property.

```csharp theme={null}
using SuperOffice;
using SuperOffice.CRM.Services;

Console.Write("Please Enter the UserName :- ");
string userName = Console.ReadLine();
Console.Write("Please enter the password :- ");
string passWord = Console.ReadLine();
Console.WriteLine();

using (SoSession newSession = SoSession.Authenticate(userName, passWord))
{
  //Gets the Appointment Agent
  AppointmentAgent newAppAgt = new AppointmentAgent();

  //Retrieves and Appointment Entity using the Agent
  AppointmentEntity newAppEnt = newAppAgt.GetAppointmentEntity(162);

  Link[] newArr = new Link[newAppEnt.Links.Length + 1];
  newAppEnt.Links.CopyTo(newArr, 0);

  Link newLink = new Link();
  newLink.Description = "Appointment Sale Link";
  newLink.EntityName = "sale";
  newLink.Id = 68; // The Sale ID to which the link refers to
  newArr[newArr.Length - 1] = newLink;

  newAppEnt.Links = newArr;

  newAppAgt.SaveAppointmentEntity(newAppEnt);
}
```

## Walk-through

There is no tool available through the services layer to just add a link to the `Links` property. Therefore, we need to create an array of type `Link` and copy the data that is held in the appointment's `Links` property using the `CopyTo` command. Then we create a new `Link` type, assign values to its properties, and assign the link to the last element of our created `Link` array.

<Note>
  By creating the new array `Links.Length + 1`, we avoid accidentally modifying any existing data items stored.
</Note>

By calling the agent's `SaveAppointmentEntity` method, we save the follow-up *and* the established link.

[img1]: ../../../../../media/loc/en/sale/sale-apt-link.png


## Related topics

- [Add follow-up](/en/diary/learn/create-follow-up.md)
- [Create follow-up](/integrations/superoffice-for-outlook/create-follow-up.md)
- [Define automatic link actions](/en/marketing/tracked-links/learn/define-link-actions.md)
- [Follow-ups](/en/diary/learn/follow-ups.md)
- [Move a follow-up](/en/diary/learn/move-follow-up.md)