The mariner's shipmates are in a constant state of change throughout the entire poem.  While they are still alive, the men change how they feel about the Mariner killing the albatross.  At first they "cry out against the mariner" because he killed the bird without a thought.  However, after the fog and mist cleared, they praised him, thinking that the bird was the cause of the fog and mist.  Then after the ship sails for a while, it stops completely, leaving them stuck without food or water.  At this point, the men once again blame him.

"Ah! well a-day! what evil looks
Had I from old and young!
Instead of the Cross, the Albatross                     about my neck was hung."

That was the end of their changes while they were alive.  Soon he is spared by "Life in Death," and the men drop to the floorboards of the ship dead, yet with their eyes all focused on him.  The only other changes that occur with the men happen while they are corpses.  Suddenly, they seem to come back to life, but they are not really alive, just "inspired" by other spirits.

"They groaned, they stirred, they all uprose,
Nor spake, nor moved their eyes;
It had been strange, even in a dream,(330)
To have seen those dead men rise."

Once they have gotten the boat going again, all of the spirits within the men leave and the men's bodies collapse once again to the floor.  That is the last of their changes.

The author rarely describes the shipmates in detail.  The focus is ultimately on the mariner and how he comes to understand the importance of all living things/creatures.  However, the changes that occur in his men (and the constant "staring" they do with their eyes) help convey his actions and show how he suffers for his wrong-doing.  Without them, the poem would lose its power and meaning.  They provide the guilt that the mariner needs to learn his lesson.