Remove the shine with a nail file or buffer
Soak a lint free pad in acetone, apply on the nail and wrap in tinfoil
Set an alarm for 10 minutes. After 10 minutes take off the tinfoil from the nail you started from and check if the gel polish is flaking off if so remove it with a wooden cuticle pusher. Continue this process one by one, do not unwrap the nails all at once as it will make the removal more difficult.