Closing activity with work left

Hi

Caccia is right : you just have to set your left work to zero.
You can do it either in the activity screen, throught the assignment update, or throught the "real work allocation screen".

I will never insist too much : left work is the key of planning.
Whatever the project managers plans, the working resource must update the left work, not only computing left = assigned - real (this is done automatically). But the resource must re-evaluate the left work !
This is the only way to give an overview of the real progress to the project manager, giving information about late ending or (as in your case) quicker done than planned.
So when work is done, the left work must be zero !!! (otherwise it means it is not completed)