hike works on one mobile one number principle! So you can log-in to one device using your hike account at a time!
How to change mobile number?
You need to delete or unlink your old account registered with the other number and, open hike again and register with the new number.
However, once you delete your account, you will loose all your chat history and free SMS as we cannot carry forward those to another number, even if the owner of both the numbers are the same. Unlinking your number will help you to retain your Circle of 'Friends' and free SMS balance!
How to change your device?
To change your device, please unlink (or logout) your account and sign up/register again. Just ensure that you unlink your account and NOT delete it. Unlinking will retain your free SMS balance, however your chat history will be deleted :)
How to Unlink (or Logout) or Delete account?
Go to Menu > Settings > Manage Account > Unlink Account/Delete Account. (For Android users, 2.5 and above : tap on options menu from your home screen > Settings > Account > Logout/Delete Account
What if deleting or Unlink (Logout) is not working?
If you are facing some error while deleting or unlinking your device, please reinstall hike and sign up again!