What action did John take regarding his tie?

Loosening the knot of a tie is a common action that indicates comfort or the desire to relax, especially after a formal event or a long day at work. When someone chooses to loosen their tie, it often suggests they are looking for relief from the tightness that can come with dressing formally. This action is often associated with an intention to become more comfortable or at ease in a situation.

The other options, while actions that can be performed on a tie, do not directly relate to the common practice of adjusting a tie to enhance comfort. Tying it tighter would create more restriction, changing the color implies an alteration rather than an adjustment, and removing it completely would signify a desire to change the outfit or appearance entirely rather than simply seeking comfort.