The phrase "change colour" can be used to describe a variety of transformations, from the subtle to the dramatic. There are several synonyms that can be used to convey this meaning, depending on the context and the degree of change. "Shift hue" is a more technical term that is often used in the context of graphic design or color theory. "Alter shade" is another option, which suggests a slight change in color intensity or tone. "Mutate tint" might be used to describe a more profound or unexpected change in color. Other options include "morph pigment," "transform hue," and "vary chroma".