if i change my gig just delivery date 3 to 1 days, its will effect my impression to lower ?
your impression is a reflection of your gig performance.
More sales with good reviews = better ranking = easier to be found = higher impression.
in other words, impression gets better as better you perform.
It might reduce your impressions for a couple of days after editing your gig. This is to be expected as your gigs get removed from Fiverr’s search for a day or two after editing them.
However, as @xuntes said, in the long run, changing your gig delivery time from 3 days to 1 is probably not gonna drastically change your gig impressions. However, it is possible that reducing the order delivery time to 1 day might improve your gig impressions as it might make your gig seem more attractive to your prospective buyers.
changing the time to deliver doesn’t affect your gig like that. I do this often. The fiverr team doesn’t need to check it manually. It doesn’t need any approval.
I believe it works for price changing too.