How to argue with postdoc hired for a project, to work on tasks from another project I have one postdoc hired on a H2020 project for 18 months. Fortunately, she worked rather well and all her tasks are going to finish soon (11th month of the project). I would like to reallocate her to other projects my group is working on now, and which fall a bit outside of the initial H2020 project, but in any case, she has the competence and capabilities to move to the other projects. I briefly talked her about this and she says it would be unethical and illegal to work on something she has not initially hired for. I think that even if these new tasks are not directly related to the H2020 project, if she works on them and gets new publications, it would be a clear benefit for her, and I told her, but she continues to refuse to work on them. How would you argue with her to move to the other tasks when the H2020 tasks are finished?
You can switch her to another project if you have the funding for it. What you cannot do is to have her work paid by one H2020 project to carry out work for some other separate project. If that's what your postdoc says, she is right.
However, even in your existing project, there should be sufficient leeway to do work on good publications, research etc. and improve the work that you have carried out on the core project. Research never stops.
Alternatively, if you have funding for another project, then you can ask for the budgets to be reassigned (Edit: if she agrees) so that she is paid through the budget of the other project. That's perfectly acceptable, albeit you may have to return some of the budget of the original project she was hired for if that is not used in its entirety.
What you cannot do is to have the original project budget pay for work carried out on another project.