A4 Template to A5 Conversion 80€

I have a finished 48-page InDesign city-magazine template set up for A4. All I need is a faithful, page-for-page conversion to A5 so that, from now on, the entire magazine will be produced only in that smaller format... (Budget: €30 - €250 EUR, Jobs: Adobe Creative Cloud, Adobe InDesign, Graphic Design, PDF, Print Design, Stationery Design, Typography, Visual Design)