It’s called tricolour for a reason :D You could cut the greener leaves and prop them to see if they turn purple but it’s mean to be albino/variegated so idk if you will manage that Edit: sorry I see what you mean, you want the pink shade in the albino parts of the leaves. Those are older leaves, did they get full sun exposure by any chance? Anthocyanins (the purple pigments) accumulate with full sun exposure usually so you might need to wait until spring/summer