What is the name of a summer flowering bush with yellow and pink variegated flowers?

It is very unusual for flowers to be variegated, usually that is a Word used to describe leaves. There are a few pink flowers with yellow throats - frangipani is one. But if you mean the flowers are pink with yellow mottling they could be Mirabilas jalapa, common name Four o'clocks. So called because they open in the late afternoon.