The article is devoted to the legal assessment of the legitimacy of changes in eligibility of the copyright works under the Czech law. The article is structured as a methodological guide. Part of the paper deals with the description of the changes of the work (f. i. the modification) which occurred or to occur in the future. Other questions are focused on the practical or legal reasons for the modification of the works. Finally, the issues are focused on the different factual and creative elements of the work that are affected by changing of the work and on the influence of the changes to the aesthetic value of the copyright work.