To change your last name on your American Airlines account, you need to follow a few simple steps. First, log into your account on the American Airlines website by visiting www.aa.com and entering your AAdvantage number and password. Once logged in, navigate to your account profile by clicking on your name or profile icon located in the upper-right corner of the page. From the drop-down menu, select “Profile” or “Account Settings” to access your personal information. In the profile section, locate the “Name” or “Personal Information” tab and click on “Edit” next to your name. Here, you can enter your new last name and update any other details, if necessary.