I am looking for anecdotes that illustrate diplomats preventing war or
hostility. Particlarly, I am amazed that when we are dealing with such
major issues as to whether a country will go to war or not, can be
effected by one man's comments and approach. As if the issues aren't
the sole determinanatns, but rather the skillful way thta a diplomat
can paint the picture can change the course of history.

Again, I am looking for examples or stories that illustrate this point

Try England's "Glorious Revolution"

No bloodshed at all.

Here is a anectote, the pingpong diplomacy.
http://edition.cnn.com/SPECIALS/cold.war/episodes/15/then.now/