> For the complete documentation index, see [llms.txt](https://docs.stacksync.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.stacksync.com/two-way-sync/features/update-sync-configuration.md).

# Manual Sync Configuration Update

You can add/update/remove tables and fields to your existing syncs from the Stacksync dashboard. Here is a [quick video on how to update sync config for HubSpot](https://docs.stacksync.com/guides/add-a-new-custom-field-to-an-existing-sync).

<details>

<summary>Adding a new column in an existing sync: Explaining automatic data backfill for existing records.</summary>

The sync configuration update is a smart feature. For example, when you add a new column, all the data of that new column will backfill for the already synced records (historical data backfill), and keep syncing incrementally for any new update in real-time.

![](/files/gnY3d4FhLXA2Oi5dE4Qh)

</details>

Updating a sync can be done in simple steps. Here is how:

<figure><img src="/files/D3xloRQ56vNoRnhE1IUJ" alt=""><figcaption><p>Update your Sync configuration GIF Guide</p></figcaption></figure>

## Step 1: Pause your sync

If your data keeps syncing while you modify your schema, table or column names/types in one of your synced apps, this could impact data in your other app in sync. This is why pausing the sync ensures maximum comfort for your sensible manipulations.

<figure><img src="/files/IS0aywqCQ3HnCaqbhDop" alt=""><figcaption><p>Pause your Sync (Switch OFF)</p></figcaption></figure>

## Step 2: Modify your schema, table or column names/types in your external apps

Now you can do any modification you would like, feel free!

{% hint style="success" %}
All modifications are allowed, no limits!
{% endhint %}

## Step 3: Update your sync configuration

In your dashboard, open the sync details of the sync impacted by your changes.

<figure><img src="/files/uvzmHdYZjEsZI6czfSYk" alt=""><figcaption><p>Open Sync details</p></figcaption></figure>

Click "Edit Sync" and follow the guided steps.

<figure><img src="/files/dJi0t1tHzqPjZypYW6z3" alt=""><figcaption><p>Start Editing Sync</p></figcaption></figure>

This process is very similar to the [sync creation process](/two-way-sync/start-here/quick-start.md) (reauthorize apps if necessary, map tables and fields) but with additional features that enable you to keep going from where you left off! 🪄

## Step 4: Confirm your changes

{% hint style="danger" %}
Modifications to sync configuration are not reversible. Double-check your new configuration before validating!
{% endhint %}

<figure><img src="/files/G1Lw8siVGK3HfUV9Qt1G" alt=""><figcaption><p>Save your Sync edits</p></figcaption></figure>

## Step 5: Turn sync on!

<figure><img src="/files/IS0aywqCQ3HnCaqbhDop" alt=""><figcaption><p>Turn sync on and data starts syncing between your apps!</p></figcaption></figure>

That's it! 🎉 Data will start syncing between your tools.