Sentinel Hub convertion from 0-255 to reflectance values

Hi ,
I downloaded satellite images sentinel L2A from sentinel-hub. Iwant to change value from 0 255 to real band value what to do?
Thank you

I suggest you check these links:

Thank you that’s great., I’m writing the script in sentinel hub and i need also to read the NDVI value in arcgis or qgis the values is steal in RGB band.