The rate remains fixed for a pre-defined period and, at the end of the period, is subject to a revision. The pre-defined period can vary from one bank to another but is generally 3, 5 or 10 years. Upon expiry of each renewal period, you can decide whether to continue with a fixed or variable rate until the end of the next period and so on.
Let’s take the example of a 20-year contract with a review period of 5 years. At the end of the first 5-year period, you decide to keep a fixed rate for the second period. For the third period, you choose to change to a variable rate. For the fourth period, you go back to a fixed rate.