Settlement versus root movement
A low panel may have lost support beneath it, while a high panel can be pushed by growing roots or affected by neighboring settlement. Those situations do not necessarily call for the same repair.
Look beyond the height difference
Check whether the panel is cracked, whether water pools at the joint and whether nearby steps, ramps or entrances will still align after a lift. Photograph the whole run of sidewalk, not only the uneven edge.
Public sidewalk responsibilities
A sidewalk along a street may be in a public right-of-way. Responsibility, permit requirements and permitted repair methods can vary. Confirm the applicable local rules before authorizing work; this site does not determine property ownership or municipal approval.
When lifting may help
An intact, settled panel may be a candidate for lifting after the cause and supporting soil are evaluated. Root-related movement, severe breakage or an unsuitable finished slope may require a different solution.
Discuss the result you need
Ask how the repair will affect adjoining panels, access and drainage, and whether additional work is needed to address the underlying condition. The contractor should confirm the scope rather than promising that every uneven sidewalk can be leveled.