E-6 Partially underexposed: Push or not?

I recently shot a roll of Elite Chrome Extra Color and accidentally turned the exposure compensation knob to -2/3 sometime during the roll. Would it be better to push +1/3 to find a middle ground, or is there enough latitude to process normally?

What do you want to do with the slides? Project them? Ilfochrome? Hybrid workflow?

Under exposed by two-thirds of a stop? I think if you shot these in bright sunlight, you may even prefer the results a little under exposed, the skies should come out a little more blue, and other colours perhaps a tad more saturated.

Personally, I'd probably process as normal, just to see the results, and depending on the subject, I may have done that on purpose anyway.

Because the roll contains shots that are exposed normally and shots that are 2/3 stop under, I would process normally. With transparency film, you will do generally do more harm by pushing normally exposed shots than you will by not pushing underexposed shots. The exception would be if you shot in flat lighting for the entire roll. In that case, a push would add some "snap" to the normally exposed shots, and keep the underexposed ones from looking like mud.