Ja tells TMZ ... he and Ashanti have decided to change the original tour name, Natural Born Killers, because they thought it would be "insensitive to the families of the victims" of senseless violence.
Ja reposted a promo for their 12-show tour with the word "Killers" crossed out. It's now called the Natural Born Tour.
Ja stressed to us ... they have a creative and First Amendment right to call the tour whatever they want, but made the change anyway.
The name's just for promotion purposes, since tickets to the show are being sold simply as Ja Rule & Ashanti.