In case you have forgotten your current password you can ask for a password reset link.
This requires you to have access to the e-mail address associated with your Aether Summon account. After filling the reset password dialog form with your e-mail address and submitting it you should receive an e-mail containing a link that you can use to reset your password.
These links are temporary and single-use so you should proceed to request them only when you're ready to take action.
After you complete the reset you should be able to sign-in normally with your new credentials.