Can i delete my old gig and create a same gig again for some reasons?
You can, but than you would lose any success earned by the deleted gig. You are probably better off keeping and fine-tuning the to-be-deleted gig. Starting over is, quite literally, starting over from scratch. Deleting gigs and creating a new copy of that gig might limit of stall your success as a seller.
If you are deleting a gig to get rid of poor reviews, that will not work. Your reviews never go away.
still not any negative reviews.