There is no rocket science behind changing the display name because Google provides a built-in option for changing the display names. Therefore, in order to change your display name or author name form Blogger Platform just login to your Blogger Account. 
Now on the Blogger Dashboard on the Top right corner of the screen, there will be an option just Select Blogger profile >> Edit Profile. We have attached a screenshot below so everyone can easily understand what we are trying to say. 
Now From here you can edit your profile as much as you like. Under the “Identity” category there will be three options such that, Username, Email Address, and Display Name. Out of these three only two are editable such that, “Display Name” and “Email Address”.
Now it is up to a person what he wants to change, either edit the “Display Name” or the email address. After customizing your profile, scroll down to bottom of the page and just save the profile by pressing “Save Profile” button.