Active job

Kitchen Floor slight relevel

my floor in the kitchen has a rise of about 7mm then levels off in all directions, I have removed the vinyl and thin particular board exposing the sub flooring. Need suggestions on if it can be sanded down or entire sub-floor needs to be removed and investigated. Am getting a new floor installed in 3 weeks time, so time critical - happy to have the particular board ripped up for further investigations if needed.