Method 1 : Master Tape>EQ>CD>EQ>New Pressing.
Method 2 : Vinyl>ADC>New Pressing
It's doubtful that track/channel-wise info can be extracted from CD source since CD is the sum of all tracks/channels mixed together. Unless one can break down a song into its component tracks, real remastering can't be done. The only thing that can perhaps be done is to do some denoising (plus tick and pop removal, if source is vinyl) and EQ-ing of the mix.
I wonder if Indian record labels retain their master tapes or not