Thank you for posting here in Community, @wenhap.
To change the balance of the account you can create a journal entry. Journal entry can be used in making an adjustment on the account and it will be posted to your GL.
To create a journal entry, here's how:
- On your left navigation pane, click +New.
- Choose Journal entry, fill out the needed information to create your journal entry.
- Click Save and New or Save and Close.
Let me share Video tutorial about journal entry: Create a journal entry in QuickBooks Online.
For your future help, feel free to read these articles:
Don't hesitate to post if you have additional questions. I'm here to answer them.