You may be able to use one of these to pump some fluid out of the dipstick tube. This is NOT a substitute for a full fluid and filter change, but you can dilute down some of the old fluid. In my cars, I was able to remove about 2 quarts through the dipstick tube. I measured the amount I removed, and replaced with a equal amount of fresh fluid. I repeated this over several days, allowing driving time to mix the new fluid with the old.
Fluid pumps are available in various types.
NOTE this only dilutes the old fluid. After about three changes, the fluid was starting to look better. When you change, fluid left in the system that doesn't drain out will be a mixture of old fluid and new, not only old. If you remove fluid through the drain tube before a change, there is less fluid spilling out to catch when you lower the pan. If weather, and or time prevent you from doing a full fluid change, you can improve the condition of your fluid.