If you have synced your wallet using an API/auto-sync then you have the option to trigger a full re-sync. This will not affect any of your previously synced transactions or any of your manual changes but it will sync any transactions that have been permanently deleted or, in very rare cases, sync transactions that the API skipped.
This button can be found on the Troubleshoot page for your wallet.
Just click on the specific wallet and then click on Troubleshoot. This will open the troubleshoot page and you will see the option to 'Trigger a full re-sync' on the right.
By clicking this option, you can choose a specific start date for the full resync, allowing you to sync only from that date onward, rather than resyncing your entire history.
🟡Note: If you see the warning "Start Date is Set" you'll need to click the Remove sync start date button before triggering the resync to ensure the entire wallet history is synced.