"make several modifications" is correct and usable in written English
You can use it to indicate that changes need to be made to something. For example: "We need to make several modifications to the budget before we can approve it."
To get to this stage, Verizon had to make several modifications.
Working with real data instead of synthetic data led us to make several modifications to the way data were corrected prior to the inversion.
Beginning in the late 1950s, Dasho Shingkhar Lam, former Secretary to Jigme Dorji Wangchuck and Sixth Speaker of the National Assembly (1971 74), was requested by the king to make several modifications to the flag; he is responsible for its current design, which has remained unchanged since 1969.
Thus, we had to make several modifications of the original model to obtain the same dynamics as described in the original paper.
If you're not using a tank and filter setup that's specifically designed for jellyfish, you'll need to make several modifications as suggested in How to Design a Jellyfish Aquarium to ensure the survival of your jellyfish.
Leaders of Mr. Fox's party, however, made several modifications.
Fossett's crew subsequently made several modifications to the car to prepare it for 800 miles per hour, including aero improvements to the rear body and wheel fairings to reduce drag.
The proposed method makes several modifications to Taguchi's method to deal with this problem.
We have made several modifications and extensions to CloudSim in order to integrate the proposed approach and to provide support for setting the CPU CAP to VMs for local resource allocation.
Although Hartshorne made several modifications to Whitehead's understanding of God, the basic structures of Whitehead's thought were continued in Hartshorne's further development of Whitehead's philosophy (Ford 1973, Cobb, 1965).
We made several modifications such as the redesign of the thermal insulating and mechanical shock protection system to adapt to the higher mechanical loads during the launch, resulting in dimensions (17 cm × 13 cm × 16 cm) and mass (1.9 kg) which are greater than for previous USOs.
