Look on the high chair for a white product sticker. Write down the model, serial numbers and manufacturing date from the sticker.
Contact Chicco Customer Service at 877-424-4226. Select "Customer Service" from the phone tree options. Advise the agent that you need to replace the seat cover on your Chicco high chair and provide the agent with the information that you wrote down in Step 1.
Follow the instructions provided by the agent to order a replacement or receive a replacement under warranty. If your high chair is still covered under warranty, this typically involves mailing or emailing a photo of the damage, along with a description; a copy of the proof of purchase; the product label information; and your name, address and contact information.
Remove the old seat cover from the Chicco high chair when the replacement cover arrives. Set it aside for disposal. Attach the new cover to the seat.