In a surprise move, singer Janet Jackson has left publicity firm Levine-Schneider, taking her trade to the New York office of Rogers & Cowan.The timing of the move caught some observers by surprise, particularly because it came in the middle of Jackson’s current world tour, the biggest of her career. The Virgin Records artist is expected to be on the road for most of 1994. Sources said the decision to change publicity firms was driven by the singer’s management team. They pointed to the longstanding relationship between Jackson’s manager, Trudy Green, and Fran Curtis, the R&C exec leading the charge on the new account. Virgin Records, which pays for an outside publicist for Jackson, has temporarily put label publicist Beth Kitrell on the road to spearhead press efforts. Curtis confirmed the move, but declined further comment. Green is on the road with Jackson and could not be reached.