Normally, the pitch tuning knob of a well adjusted Moog Etherwave will have enough headroom to compensate temperature effects.
When the instrument is adjusted for a center position (12 o'clock) of the pitch knob at normal ambient temperature (21°C / 70°F), you will have to turn it about 1 hour clockwise for each 3°C / 5.4°F above and about 1 hour counterclockwise for each 3°C / 5.4°F below this standard temperature.
An internal retuning is only needed if you reach the limits of the pick knob without satisfying results. In that case you would have to adjust just the middle one (L6) of the three variable coils which are inside. Do NOT touch the others!
A special red plastic tuning tool has been provided with your ether wave for this purpose. Do NOT use metal tools, you risk to destroy the graphite slugs of the coils.
Now it depends which version the coils inside are. Do they have a hexagonal hole or a "classical" straight slot?
If it is the straight slot, it is simple. If you are at the clockwise limit of the pitch knob, turn L6 also somewhat clockwise (and vice versa), about 1/8 turn. Put the cover back (that is important since it strongly influences the pitch field) and check if you are now able to tune your Etherwave correctly with the pitch knob.
With the hexagonal slug, it's just the other way round. If you are at the clockwise limit of the pitch knob, turn L6 somewhat counterclockwise (and vice versa).
Repeat this procedure until you are satisfied.