You cannot change the email tied to your Sprintax account.
We can add a secondary email for correspondence, however you will need to use the original email as an username to log in (that would not cause any issues as all the information you will need to be provided with, will be sent on your active email address).
Also please note that reset password links and passcodes can only be sent to the email used for creating the registration.
Alternatively you can create a new account with an updated email.