1. Exceptions about acceptance
2. Acceptance of an offer

Unilateral acceptance of a contract can only take place by means of actual performance. This is in contrast to bilateral contracts, which are accepted by means of a promise made.

To use an example to explain unilateral acceptance, imagine Michelangelo agreed to pay Picasso $500 for painting his beach house. Picasso accepted the offer and agreed to do the job. A couple of days later, before Picasso started painting, Michelangelo changed his mind and recanted the offer that he made to Picasso. Under these circumstances, Michelangelo would be allowed to take his offer back, because Picasso had not started the work yet. According to the principles of unilateral acceptance, promises are nothing and performance is everything.

The way in which a contract needs to be accepted will vary depending on the offer. If a promise is exchanged for a promise, then the offer is a bilateral contract.

Exceptions about acceptance

The only exception to the rules about acceptance in a bilateral contract is if the job is already done before the offer is recanted. To use the example of Michelangelo and his beach house again, consider a different scenario:

  • After receiving the offer of $500 for the job, Michelangelo did not respond.
  • Despite his lack of response, he went to the beach house the next day and started painting.
  • Two days later, he was done, and then Picasso retracted his offer.

In this scenario, if Picasso were to fail to pay Michelangelo for his work, he could be sued and would lose the case. The fact that Michelangelo failed to respond to the promise with a promise of his own, he offered full performance. In a case like this, full performance proves that he accepted the offer, and a contract would thus have been formed.

It is important to note that although a promise is required in order for a bilateral contract to be accepted, this promise does not have to be given verbally. A simple nod of Michelangelo's head could construe acceptance of the offer to paint Picasso's house. Alternatively, if the pair had been at the beach house when the offer was made, Michelangelo could simply have picked up a brush and started painting, provided that Picasso could see what he was doing.

In a case like this, the fact that Michelangelo immediately got started on the job, in full sight of Picasso, would form affirmation and nonverbal acceptance of the offer.

Acceptance of an offer

In most circumstances, an offer must be accepted by means of communication with the person making the offer. If the person being offered a job wishes to accept it, he needs to tell the person who has offered him the job. However, in certain circumstances, the person offering a job can expressly waive this requirement, meaning that the offeree is entitled to accept an offer without expressly informing the person making the offer.

According to the general rule, a contract is complete once the job has been done. However, the person making the offer is not obligated until such time as the contractor informs him that the job is done. For example, consider the following scenario:

  • Michelangelo had agreed to pay Picasso $500 for painting his beach house within the next two weeks.
  • On the day that he completed the work, Picasso informed Michelangelo that the job was done.

Only then would Michelangelo be obliged to pay Picasso for the work.

In a situation like this, the contractor would need to tell the client the job is complete within a reasonable time frame. If this didn't occur, then the contractual obligation would fall away. As an example, if Michelangelo promised to pay Picasso $500 for painting his house within the next two weeks, but was only told six months later that he had finished the job, Michelangelo would no longer be legally required to pay Picasso.

It must be noted that if Michelangelo tried to tell Picasso that the job was complete, but had not been successful, then Picasso would still be required to pay. This would apply if, for example, Michelangelo had written Picasso a letter telling him that the job was done, but the letter got lost in the post.

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