After having your home reassessed, you can file a grievance to contest the new assessment and subsequent property tax increase. You should be prepared to show evidence for your claim; this usually involves showing that the assessed value differs from the market value of the home. Additionally, if your community doesn’t assess at 100% of market value, but assessed your home at 100% of the value, you can appeal on these grounds.
If you are unsuccessful with your grievance, you can chose to appeal further in a Small Claims Assessment Review.
Any taxpayer that pays property taxes can file a tax grievance (residential or commercial).

Savings depend on the degree of over-assessment and the success of your grievance.
Claimed as a reduction in future property tax bills.
How to Claim
Complete Form RP-524 and file before the fourth Tuesday of May (or before your local deadline).
You can read about the whole process in NY Department of Tax’s guide here.
For assistance filing your property tax grievance (for example, helping you determine the market value of your home based on a record of improvements done), you can contact savings@castlepay.co or schedule a free consultation here.
Required Information
You should have information on your home’s market value, and how you reached the conclusion the assessed value is too high. You can review how to calculate this here.
Timeline
Grievances typically need to be filed by the fourth Tuesday of May, but individual municipalities may vary in their timing.