Hello there, emma. Reconciling without a subscription or resubscribing isn't possible. QuickBooks requires an active plan for any account access, including reconciliation tasks. With that in mind, you have two main workarounds.
First, you can export your client's data to perform the reconciliation outside QuickBooks. Otherwise, your client can resubscribe for a single month to complete the work inside the program.
We'll be available for any additional questions about these options.