If you are doing this kind of rescheduling on a more frequent basis (for example, if you are dispatching activities within your organisation as project manager), i would consider using either taslist plus or calender plus from durkin computing. www.durkincomputing.com
These addons function as an extra shell around / in Act where information is being presented in userdefinable ways, including the possibility to reschedule multiple tasks.
Rene van der Velde
aka The Dutch Betatester
Rene van der Velde The Netherlands aka 'The Dutch Betatester'