If you would like to drop one session while continuing to latch in the evening and at night, I would propose you drop the 5pm session. Do so gradually by slowly delaying the 11am session a little later each day till you can have just one session in the mid day (such that it could last till you latch your baby at your in-laws).
You can also consider reducing the pump time for the evening session when you are making the initial adjustments for the timing to help your body adapt, and (hopefully) minimize any potential discomfort from the changes.
Hope this helps!
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