you can file dispute to the AMC (the bank actually not contract the appraiser but the appraisal management company) the dispute must including a n analysis why you need dispute. for example, the comp is wrong. There are better comps there but the appraiser use the another one. The property is rented but on report show vacant. Indicate all mistakes. You may work with an good loan originator or realtor oe a third party appraiser to find such mistakes.
ask the AMC refund and pay demage. (prepare sue the AMC) not the appraiser. If you go court, hire an attorney.
And file compliance to the state regulartory agency (who issue appraiser's license)
