Agree on the date and scope
Use the same supplier account, entity, currency, and cutoff date for both sides of the comparison. Retain the original statement and ledger export so another reviewer can reproduce the work.
Match the individual items
Compare invoices, credit notes, payments, and allocations. Separate matched records from unmatched items. A balance difference may arise from timing, an unrecorded invoice, a missing credit, or an allocation issue; it does not establish an error by itself.
Investigate the difference
Identify the document or confirmation needed for each unresolved item. Note the amount, reason, owner, and next action. Draft supplier questions using the actual references rather than a general request to explain the account.
Close with evidence
An agreed correction needs the relevant approval and accounting entry. A credit needs application evidence where closure depends on its use. Retain the final reconciliation and the evidence for outstanding follow-up.