What happens if the buyer wants to change key terms after the LOI is already signed?

Generally, they're allowed to, at least legally — since price and structure in a typical LOI are non-binding, either side can propose changes after signing without that itself being a breach. Buyers sometimes come back after due diligence, or simply after more thought, wanting different terms than what the LOI originally described, and there's usually nothing in a standard LOI preventing that from happening.

The practical difficulty is the position it puts a seller in, especially one bound by exclusivity. Having given up the right to talk to other buyers, you may feel pressure to accept a buyer's revised terms rather than risk the whole deal collapsing with no other options readily available — a dynamic sometimes called "retrading," and it's a known risk of exclusivity rather than something unusual or improper on its own, though a pattern of bad-faith retrading can be relevant if your LOI includes a good-faith negotiation clause.

Sellers who want to reduce this risk can build in protections upfront: milestones that limit how long exclusivity runs before a definitive agreement is expected, or a right to terminate exclusivity if terms change materially. A Treadstone business lawyer can help structure that protection before you sign, not after a buyer comes back wanting less.