Which of the following is NOT a scenario where alterations to agreements are allowed?

In the context of real estate agreements, alterations to contracts are typically restricted to ensure that all parties are in agreement and aware of any changes. The correct choice indicates a scenario where alterations are not allowed. An agent altering terms in the buyer and seller agreement without the consent of all parties involved undermines the integrity of the agreement. In a real estate transaction, both the buyer and seller must agree to any modifications, and unilateral changes could lead to disputes or legal issues.

In contrast, the other scenarios involve situations where alterations may be permissible. For example, if a person is altering an agreement that they are party to, it generally means that they can negotiate or amend terms as long as all involved parties consent. Similarly, a licensee's employment agreement can often include amendments based on mutual agreement between the licensee and the employing brokerage. Lastly, a listing agreement on behalf of the firm may allow for modifications as it typically requires the broker's and the seller's consensus to change terms related to the listing.

Thus, the expectation of mutual consent in altering the buyer and seller agreement makes it clear why that scenario is not permissible without agreement from both parties involved.