You don't have to.
The tasks will automatically be resent after your computer fails to report a result before the deadline.
Just for future reference, if you are detaching from a project, work units are recycled much quicker if you select "No more work" for the project, abort all the tasks in progress and in your cache, then detach. Aborting the task lets the system know that you will not be submitting a result and can therefore send it out immediately.
My Top 5000 Primes:
110059!+1 is prime! (FPS)
14493618614235*2^666666-1 is prime! (SGS)