A side letter agreement is an agreement that is made between two parties in addition to a primary agreement or contract. These agreements are often used to modify or clarify the terms of the primary agreement. They are typically used when there is a need for additional provisions that are not covered in the primary agreement.

Some examples of side letter agreements include:

1. Non-Disclosure Agreement (NDA) Side Letter: This type of side letter is typically used when there is a need to modify the terms of an NDA. For example, the parties may want to extend the period of confidentiality or modify the scope of the information that is covered by the NDA.

2. Amendment Side Letter: This type of side letter is used when there is a need to modify the terms of a contract. For example, the parties may want to change the payment terms or modify the performance obligations.

3. Waiver Side Letter: This type of side letter is used when there is a need to waive certain rights or obligations under the primary agreement. For example, the parties may want to waive the right to terminate the agreement for a certain period of time.

4. Termination Side Letter: This type of side letter is used when there is a need to terminate the primary agreement. For example, the parties may want to terminate the agreement early or extend the termination date.

It is important to note that side letter agreements should be carefully drafted to ensure that they do not contradict or conflict with the primary agreement. Additionally, they should be clearly worded and easy to understand to prevent any misunderstandings or disputes.

In conclusion, side letter agreements are useful tools in modifying or clarifying the terms of a primary agreement. They can be used in a variety of situations and should be carefully drafted to ensure their effectiveness. If you are considering using a side letter agreement, it is recommended that you consult with a qualified attorney.