Half reactions don't have to be redox?

[Jessa Maheras 4F]

Hey, I'm confused on the acknowledgement in the textbook that in order to express a reaction in half reactions, the reaction doesn't have to be redox. How is this so? How can you express non-redox reactions as half reactions?

[Sally Qiu 2E]

i encountered a practice problem that had this situation, i think the half reactions add together to make a bigger half reaction. therefore it doesn't make the reaction a redox.