Let's identify the reasons for the discrepancy for that specific month so that you can correct your entire reconciliation, Chaman.
If there are transactions that need to be deleted, we can manually unreconciled each incorrect transaction one at a time.
If you prefer to undo the entire reconciliation, then we can only do it using QuickBooks Online Accountant (QBOA).
Here's how to remove individual transactions manually:
1. Click the Gear icon at the upper right corner.
2. Select Chart of Accounts.

3. Locate and choose the account you’re working on, and click on Account History.
4. Select the transactions you want to unreconciled
5. Continue clicking the R status until it appears blank or displays C to clear. Before removing the incorrect transaction, make to have your bank statement to cross reference to your QuickBooks records.
6. Click on Save.
7. Choose Yes to confirm.

Also, I'm adding this page for a step-by-step guide to help you identify and fix problems so you can complete your reconciliation: Fix issues for accounts you've reconciled in the past in QuickBooks Online
Let's also look at how to avoid unintended changes to your upcoming reconciliation transactions, refer to this page to learn how to close your books: Close your books in QuickBooks Online.
You're always welcome to post again here and ask any other questions in the Community.