You have to be careful because legal problems can result in litigation, and litigation is expensive, time consuming, stressful, protracted, and uncertain in outcome. You want to get legal advice from an experienced real estate lawyer before you act.


Rescission
In several provinces of Canada and states in the United States there is a “cooling off” or rescission period, whereby the purchaser of a new property has a period of time (usually from three days to thirty days) to back out of the contract by giving notice to the vendor in writing before the deadline. The vendor is obliged to pay back without penalty all the money that the purchaser has placed on deposit. In cases where legislation does not give an automatic right to rescission the documents that are a part of the property package may have a rescission period built in. If you do not have a statutory (by legislation) right to rescission and it is not part of the documents relating to the purchase of a new property, then you may want to make it a condition of your offer.

Specific Performance
If the vendor or purchaser refuses to go through with a purchase and sale agreement when there are no unfulfilled conditions attached to the agreement, the other party is entitled to go to court and request the court to order that the breaching party specifically perform the terms of the agreement, eg, complete the transaction. This commonly occurs in a descending market price scenario. The party who succeeds in obtaining the court order would be entitled to ask for the court costs of the application from the court. 

Damages
If one party refuses to complete the agreement, instead of suing for specific performance of the terms of the agreement, the other party can sue for damages. Damages mean the financial losses that have been incurred because the other party failed to complete the bargain. There is a basic legal maxim that says “to get financial damages (compensation), you have to prove you have suffered financial damages (losses).”
If the house value has not gone up or down by the purchase date, and if, for example, another purchaser was found, and no other losses occurred, the vendor (in this hypothetical example) could attempt to claim the deposit funds as “liquidated damages.” This amount is generally negotiable, unless it states clearly in the agreement of purchase and sale that the deposit funds automatically and irrevocably go to the vendor if the purchaser does not complete.

Conditional Contract
If the vendor or purchaser has preliminary conditions built into the purchase and sale agreement (“subject to” clauses), and those conditions cannot be met, no valid binding contract exists and neither party is liable to the other, and deposit funds are returned to the purchaser.

Void Contracts
A contract is void and unenforceable if the required elements that make up a contract are not present, or if the contract is prohibited by statute for some reason, or the one party is minor, or there is no intention to be bound, or no right to sign, etc.
The most important document you will sign will be the offer to purchase, which if accepted becomes the agreement of purchase and sale. It sets out the terms and conditions between the parties and, as in any contract, it is legally binding if no conditions exist in the contract that have to be met before it comes binding. Of course, there can be verbal contracts, but all contracts dealing with land must be in writing to be enforceable. That includes the purchase and sale agreement or a lease, which of course is also a contract.

Voidable Contracts
If one of the parties has been induced into entering the contract on the basis of misrepresentation, whether innocent, negligent or fraudulent, that party may be entitled to void the contract. If the misrepresentation was innocent, generally only the contract can be cancelled and any money returned, and no damages can be recovered in court. If there is negligent or fraudulent misrepresentation, however, not only can the contract be cancelled, but damages can also be recovered in court. For example,  if the purchaser finds out before completion that the representation of the vendor or the vendor’s agent is untrue (e.g, that the condo can be rented out under the condo bylaws, but it turns out that is not correct), then the purchaser could get out of the contract and sue to recover damages, if any can be proven.

These are just some illustrations of the types of factors that could impact on the validity or enforceability of the contract. You can see how competent legal advice in advance from a skilled real estate lawyer is necessary to minimize potential problems.