Abort Task?

Greetings everyone. I just messed up and essentially told boinc to load 10 days worth of work on my computer. This specific computer typically almost doubles the initial 'guess' as to the time it takes to do the work. Rather than have tasks sit here for two weeks until they become late, can I abort them and when I do, does that put them back into queue for someone else to pick up or does it cause them to be lost?

Thanks and sorry!!

Aaron