australia
Changing mind about agreement before taking effect
<p>If two parties A &amp; B both agreed to sign off on a development program document on x date, where the development program document states the agreement will take effect on Y date, however A changes their mind and sends notification in writing to other party B stating they reject the program on date C, prior to/ before agreement takes effect on Y date</p>

<p>Does A have to continue to accept agreement or does it become null and void?</p>

<h2>Agreements can be cancelled at any time, contracts can’t</h2>
<p>If the agreement is a contract (<a href="https://law.stackexchange.com/q/6263/344">What is a contract and what is required for them to be valid?</a>), then it’s binding and failing to fulfil the obligations in it is a breach that can lead to a lawsuit. The innocent party is entitled to be put in the position they would have been in but for the breach. So if B expected a $5 million profit (or whatever) then A must make B whole by paying them $5 million (or whatever).</p>
<p>If the agreement is just an agreement then either party can cancel <em>unless</em> they are <a href="https://en.m.wikipedia.org/wiki/Estoppel" rel="nofollow noreferrer">estopped</a>. Estoppel is a complex area of equity law which in this instance says if A made a promise and B relied on that promise to take or not take some action and A knows B is doing that and B will suffer loss if A breaks that promise then A can’t break their promise. More or less, as I said, estoppel is complicated.</p>
