So you see, the response requested is indicated in the very form and name of the document itself. The Letter of Intent has no established place in International trade law. Where they are used _ rarely _ is in some small niche internal markets and trades. The RFQ, Request for Quotation, a standard protocol in the business world, is what most brokers actually want when they err in using an LOI.
On Offer acceptance there is either a contract generated or a pro forma invoice generated. Since the offer is binding once accepted, the offer if well enough detailed and advised can and often does take the place of the contract. Customarily in Real Estate transactions the purchase offer itself is generally also the contract for purchase as well. The offer becomes a binding contract once accepted.