= Solution
For a concrete choice, draw the intermediate in the planar ring orientation used in the question and put the allylic OH on the upper face, with a solid-wedge C-OH bond. Fix either configuration at the R-bearing and methoxy-bearing centres and retain it throughout; no absolute configuration is specified by the question.
Draw the six-membered rearrangement array with its allylic C-C-C segment along the same ring edge and the O-ketene-acetal tether above that edge. Suprafacial transfer forms the new ring-carbon–CH$_2$CO$_2$Et bond on that upper face: draw it as a solid wedge, replacing the original allylic OH with the shifted double bond. The R-bearing and methoxy-bearing <stereocentres> retain their configurations. The opposite OH epimer transfers the tether from the opposite face and gives the opposite new <stereocentre>. Favor the chair-like transition structure that puts the larger tether substituents outward. This explicitly correlates the selected OH face with the new bond rather than invoking a freely rotating allylic <carbocation>.
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