R-6.01, r. 4.1 - Rules of Procedure of the Régie de l’énergie

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39. The Régie may, at the request of a participant or on its own motion, call witnesses and require the production of documents.
Where applicable, the Régie issues a summons to appear, and the participant who has requested it is then responsible for serving the summons on the witness concerned at the participant’s own expense.
The summons to appear must be served at least 5 working days before the date scheduled for the witness’s appearance, unless the Régie issues special instructions.
O.C. 1098-2014, s. 39.