I have to assume you have the Hydroptic 6 and not a Hydroptic 6A The older Hydroptic 6 machines are a manual toolchange, not an electric change like the later 6A's
The Hydroptic 6 the spindle has to be raised to the uppermost position, which locks the drawbar, but you get the tools out by using the hexwrench and rotating the spindle right above the taper.
The thread direction is typical right hand. If the tool has been in the taper for quite awhile or left in after the machine was hot, you'll have to give it a pretty good tug to unlock the tool. When you're rasing the spindle up to the toolchange postition, you'll feel a spring pressure for the last inch. Once the spindle is up all the way, put the wrench into the hex on the right side of spindle and pull the wrench TOWARDS you.This is the direction for releasing the tool. For reinstalling the tool you can thread it up until it seats, and then install the wrench on the LEFT side of the spindle and pull towards you. This will tighten the tool in the taper. I have both a Hydroptic 6 as well as several 6A's in my shop, so certainly know how to install the tools. SOME of the Sip tools have a rectangular projection above the Morse, and this has to locate into the recess at the base of the spindle. Then there's the external taper, that the toolholder needs to be oriented by matching up the dot on the tool to the dot on the spindle. To install these tools, you have to just rotate the spindle until the taper fully seats. Ditto for removing them.
If the tool refuses to budge even after you've reefed on the short wrench, just tap the side of the toolholder while it's still tensioned with the drawbar, with the side of your wrench. Just a slight whack is usually enough to pop the taper out.
Remove the toolholder after you're done running the machine. It makes it WAY easier to get out than fighting with it after it's been in there for days ( or weeks)