The input line voltage can be converted from 400 VAC to 208 VAC or 208 VAC to 400 VAC. This is described in appendix C "Line Voltage Conversion" in the Operating Guide on page 121. The guide is located at http://literature.cdn.keysight.com/litweb/pdf/5964-8267.pdf
You also need to order a kit to do this. The part numbers are listed in the manual. Also make sure that you use the proper line cord once you do the conversion.
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