I am looking for locking reconciliation so others cannot change any payments, please advise,

Good day, infotechvalley.

For now, there isn't an option to lock a reconciliation in QuickBooks Online. However, you can close your entire books to prevent other users from changing transactions without providing a password. 

Here's how:

1. Go to the Gear icon ⚙ and then select Accounts and Settings.
2. Proceed to the Advanced tab.
3. Click Edit ✎ in the Accounting section.
4. Select the Close the books checkbox or swipe it to the right..
5. Enter a closing date. 
6. Select the Allow changes after viewing a warning and entering a password. Please take note that you can always edit the date in this field after reconciling the succeeding month's data. You can check out this article for more details: Edit Your Closed Books. 
7. Click Save, then Done.

Additional details and guide links about the Reconciliation feature are discussed here: 

• How Do I View, Print, Or Export A Reconciliation Report?
• Enter An Adjusting Entry For A Reconciliation In QuickBooks Online

I'd also to share this article in case you need more reference and guidance with your year-end tasks: QuickBooks Online Year-end Guide And Checklist.

The Community is always here if you need anything else.