I need to know if after I filed chapter 13 my job is cutting hours and ending a position could I change my mind and file chaptet 7 and keep my car

You can convery from chapter 13 to chapter 7 assuming you qualofy and meet the new means test that may be required. Whether you are able to keep the car will depend on if the car is already paid for. If it is not, you can reaffirm the debt with your creditor and continue to make payments. If you do not, they will likely repossess the car and sell it, but you will not owe the remainder of the debt.