Yes, if you use a script. See this post:
http://forums.omnigroup.com/showpost...41&postcount=2
The script marks the one you want to reschedule as complete, causing OmniFocus to generate the next one at the scheduled time. The script then turns the action marked complete into a non-repeating action, marks it incomplete, and bumps the dates by the amount you requested. If you want to adjust the dates asymmetrically, you'll have to adjust them by hand, but either way, you won't perturb the regular repeat structure.