You can upgrade at any time: i.e. a) switch from the Now account model to Change or Zero, or b) switch from the Change account model to Zero. In these cases, we will credit the months already paid to the new price. The 12-month term starts again when you upgrade.
You can also switch from the monthly payment method to an annual payment option at any time. However, you cannot switch from annual payment to monthly billing, as this is only possible at the end of the 12-month term.
A downgrade is also only possible after the 12 months have expired. This means a) switching from the Zero account model to Change or Now, or b) switching from the Change account model to Now.
If you are happy with your account model and do not change it, your account model will automatically be extended by a further 12 months after the 12 months have expired.