Resize and seperate PNG Poster for Large Print

I have a finished design saved as a png, but the file isn’t set to the exact size I need—1189 mm × 841 mm. Please adjust the artboard so that the final output matches those dimensions precisely, keeps proper proportion, and remains sharp when printed at full A0 scale.

The only problem is sizing; colours and artwork are already approved. Once resized, supply a press-ready PDF (300 dpi or vector, with bleed and crop marks if required) so I can hand it straight to the printer without further tweaks.

Deliverables
• Print-ready PDF at 1189 mm × 841 mm
• Confirmation that resolution and proportions are intact

I’ll provide the original PDF as soon as we start. Let me know if you need any extra details.