Making the singing voice louder while keeping the orchestra down (same audio track)

Hi everyone,

I'm using Premiere Elements 15 and have a clip (unfortunately, it's just this one audio track, i.e. no separate tracks) with a duo singing and the orchestra playing in the background. However, the orchestration is really not that backgroundy, as the voices are too quiet in comparison. Is there any setting in the software that would allow me to make the voices louder? If so, I have been unable to find it

Many thanks for your help!