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

# Changing the email or ID of a customer using 'alias'

> Use the re-identify or alias method to update a customer's ID or email address.

*This only applies to customers using Vero's own Javascript API Library or Segment.com's Analytics.js Javascript library.*

Sometimes you will track and cookie a customer using a random identifier, or their email address, and later you will want to update this value with a unique identifier (ID) from your own database or system.

## Re-indentify

For example, if you had called the `identify` method and tracked a customer with the email **[tyrion.lannister@casterlyrock.com](mailto:tyrion.lannister@casterlyrock.com)** as a subscriber on your blog but, after they signed up for your free trial, wanted to identify them with your database identifier of **1285** , you can use Vero's `re-identify` method to update the customer's profile.

To learn about the re-identify (or alias) method in detail, refer to our [API Reference Documentation](/api-reference/users/alias).

An example of the re-identify method is below:

```
<script>
        _veroq.push(['reidentify', '1285']);
    </script>
```

## Segments alias

Segment's `alias` method works in the same way. Vero is the only email marketing platform that works with Segment and provides an `alias` method, giving you a lot of power and flexibility over how your customers are tracked.