A chemical reaction may undergo different reaction mechanisms at different temperatures.
In this case, a Van t Hoff plot with two or more linear fits may be exploited. Each linear fit has a different slope and intercept, which indicates different changes in enthalpy and entropy for each distinct mechanisms. The Van t Hoff plot can be used to find the enthalpy and entropy change for each mechanism and the favored mechanism under different temperatures.
In the example figure, the reaction undergoes mechanism 1 at high temperature and mechanism 2 at low temperature.