Deleting users and candidates from TALEO

Summary

is the delete necessary for a new export from fusion and is there an automatic way to perform

Content

Hello ,

We would like to have a new export of all the users and candidates from fusion into Taleo. 
MoSt of the users already exists in Taleo but we would still like to export all again into Taleo. 

I would like please to know if deleting the users from Taleo is neseccary for that export into Taleo, and 
if there is an automatic way to perfrom that ? or delete user and candidates one by one ?

Please let me know,
Thanks a lot ,