A renegotiable rate mortgage (RRM) consist of a series of short term loans but fall under the umbrella of a main long term mortgage.
The short term loans usually run for about 3 to 5 years and are lined up with each other so that as soon as one matures, another ones takes over the torch.
The term used to describe this passing of the torch is renegotiate, renew or rollover.
Which explains why it is also known as a rollover mortgage.
It is like a hybrid of FRM and ARM.
Once a segment expires and a new one commences, a new installment amount would be calculated based on the new interest rate.
It can sometimes be present in a contract as a renegotiable rate clause.