Go to your Profile. Click Edit tab under your Display Pic and there you can Edit your name for 50Diamonds'''50 Diamonds'''.
===What is attack range and how is it calculated?===
Attack range is 10% for the first 20 Levels and 20% for the rest. This attack range is calculated from the attacking player. For example: Level 100 can attack as low as Level 80 (20% of 100 = 20)