Assistance in the collection of taxes: mutual acceptance allows cross-border enforcement and conservancy measures under domestic law. Assistance in the collection of taxes requires Contracting States to accept and collect each other's tax claims or to take conservancy measures, including asset freezing where their law allows, applying their own enforcement procedures as if the claims were domestic. Accepted claims do not gain domestic time limits, statutory priority, or adjudicative remedies in the requested State. Requests may be suspended or withdrawn if conditions change, and assistance may be refused where action would conflict with domestic law, public policy, lack of prior reasonable collection efforts, or where administrative burden is disproportionate.