In word, highlight the citation you want to change. Click on 'Edit and Manage Citations' in the EndNote tab. A box will appear like the one below. Beside 'format', click on the arrow next to 'default' and from the drop down menu select how you want your citation to display e.g 'Exclude Author', 'Exclude Year' etc.
Below is a video giving an overview of inserting and managing citations with Cite While You Write (CWYW), including how to exclude an author or a year.