“Modification” is not exactly synonymous with “amendment,” for the former term denotes some minor change in the substance of the tiling, without reference to its improvement or de- deterioration thereby, while the latter word imports an amelioration of the thing (as by changing the phraseology of an instrument, so as to make it more distinct or specific) without involving the idea of any change in substance or essence.
https://thelawdictionary.org/modification/