ByJohn S. McClenahen Relocation is on the rise among jobless managers and executives. So don't be surprised to see more moving vans on the road during this first half of 2001, says Challenger, Gray & Christmas Inc., a Chicago-based outplacement firm. It figures that 26% of job-seeking managers and executives took positions in a new city during the final calendar quarter of 2000, a 30% increase from last year's first quarter, when 20% relocated. "With the economy faltering, employers simply are not hiring as quickly," says John A. Challenger, the firm's CEO. But, despite the fact that the risks of moving increase as economic stability decreases, people are more willing to leave their safety nets if that means finding a job quicker."