11+ Addendum Agreement Templates. Even after a contract is completed and in full force, there are some changes that need to be updated according to time and situation. That’s when you create an addendum contract. It specifies all the terms, clauses and sections that need to be changed in the original contract. What Is a Contract Addendum? A Contract Addendum is a document that is used to add certain terms and conditions to an existing contract. This can be used when there are terms in a contract that were left out or not included in the original contract. THIS ADDENDUM TO EMPLOYMENT AGREEMENT (the “Agreement”) is made and entered into on December 29, 2012 by and between Lightwave Logic, Inc., a Nevada Corporation (the “Company”); and Louis C Glasgow (“Employee”). This Agreement amends and modifies as follows that certain Employment Agreement (“Employment Agreement”) dated November 1, 2011 made and entered into by the parties hereto.