Only the user of an account can change the email address. To change the address follow the steps below. The email will be used to create an email signature for your send-outs.
Go to Settings > My profile.
Click on the padlock beside the email address.
Enter the new email address.
Go to your email inbox and you will receive a verification email from us where you need to click Verify e-mail
Once you have done the above step you will successfully have changed your email.
Now you can use the new email to log in to the account. The password won't be affected by changing the email.