I have some tasks for a project on one host that obviously won't all finish before expiration. Another host could handle some of them. Rather than aborting tasks is there a way to move some tasks from one host to another?

Not really. First of all, the tasks must be uploaded by the same host that downloaded them or else they will be discarded.

Further, you would have to create a separate BOINC installation on the other host, because you can't (easily) merge tasks.

So, in all, I'd say you'd better abort (and report) those which would be far over the deadline.

Gruß,
Gundolf

O.K. Thank You.

Depending on the project, you might still get credit even if the tasks are sent in after the deadline... Some projects are very strict about this, while other simply use it as a scheduling aid.