How do you tie a knot without letting go of eaither end?

You can't tie a traditional knot without letting go of at least one end at some point. The act of tying a knot involves crossing and looping the rope or string around itself, which necessitates releasing one end to allow for the manipulation.

However, there are ways to create something similar to a knot without releasing either end, using techniques like:

* Overhand loop: You can create a simple loop by wrapping one end of the rope around the other, forming a circle. This isn't technically a knot, but it does create a secure loop without letting go.

* Slipknot: A slipknot can be created by making a loop and passing the working end through it. This allows you to adjust the loop size, and it can be secured by tightening the loop around something.

* Special knot types: Some knots, like the "Figure-Eight Knot" and the "Double Figure-Eight Knot," can be manipulated to secure a rope to itself without releasing the ends, but they involve specific techniques and might not be suitable for all situations.

If you are trying to tie a knot for a specific purpose, it might be helpful to describe the situation so I can provide more specific advice.