What is the ERC (European Research Council)? Find more information here:

-ERC website
-Euresearch: the Swiss guide to European research & innovation

The panels can reallocate submitted proposals. At what step in the evaluation is this done?

Normally, proposals are shifted to a different panel than that chosen by the applicant at the very beginning of step 1 evaluation. A proposal may be reallocated to a different panel with the agreement of both panel chairs concerned when necessary due to the expertise required for its evaluation.