The email address once created can't be changed at all. You can create a new but can't modify your existing one. You can export your emails and contacts to new address. But the user name can be changed very easily.In this Tutorial we will guide you how to change Gmail Username in very few steps.
HOW TO CHANGE GMAIL USERNAME IN SIMPLE STEPS:
Step 1 : Login/Sign In with a Gmail account on your PC or Desktop.
Step 2 : Click the Gear on top right corner.
Step 3 : Click settings
Step 4 : Select Accounts and Import Tab
Step 4 : Locate your email address in the Send mail section
Step 5 :Click Edit & Enter the new username in name section
Step 6 :Click save changes
You can add or remove dots from username but that is not vital. You can change the username but not email id.