Can I change an oval shape to a round shaped pool

I have a 5.94 x 3.66 mtr oval pool which I’d like to turn into a round pool.  If the length of the wall was around 55ft would this translate to about a 17ft round pool.  I’d have to buy a bit more to make it into an 18ft I guess.   Also would all the resin top decks have to be replaced or could I use all except the 4 middle ones of the oval pool.  I know this would also need 4 of the bottom rails and coping rails to be changed.  What about the cover plates, would all but the 4 middle ones work?.   Thank you.