When writing an addendum, all specific clauses, terms, sections and definitions that are being altered from the original agreement need to be listed. The purpose of an addendum is to alter only the parts of a contract that all parties wish to change while making sure that no loopholes or unwanted consequences are created in the process.
An addendum can prove difficult to write since contract law states that every party has to adhere to the contract as it is originally written. When the addendum is created, it should look as close to the original contract as possible, which includes the font, typeface and margins.
The first part of the addendum lists the parties included in the original contract and describes what specific terms such as "contract" and "the addendum" mean. The most essential part of the addendum is that it clearly defines the parts and terms of the original contract that are being changed. The new terms of the contract are written next to the old terms. The creator of the addendum can also use strikethrough and bold styles to bring attention to all parts that are added to or removed from the agreement. Attorneys should often be consulted regarding the writing of an addendum.