If a trial or hearing has been commenced and the judge is unable to proceed, any other judge may proceed with it upon certifying familiarity with the record and determining that the proceedings in the case may be completed without prejudice to the parties. In a hearing or trial without a jury, the successor judge shall at the request of a party recall any witness whose testimony is material and disputed and who is available to testify again without undue burden. The successor judge may also recall any other witness.