Hello there, @Yuki1.

Here's how:

1. Log in to your account.
2. From the left menu, click Clients.
3. Click the client's name.
4. At the top right, click the Drop-down arrow beside Edit client.

You can read this article for your reference about undoing a reconciliation: How to Unreconcile a Transaction or Undo a Reconciliation.

You can always drop by here in the Community if you need a helping hand. I’l be around to help. Have a great rest of your day.