The biggest issue on when to overrule,,,,,,,,,,,,,,,,,,,,,,,,,,try to develp the "get it right" idea in your partners heads.
On a close play, take a look at your partner to see if they have that deer in the headlights look. If they do, casually have a conversaton with them later and encourage them to not be so over run with ego that they won't ask for help.
But like so many said, YOU NEVER OVERRULE.
You simply give information to your partner to allow them to make the correct ruling.
If you can trust your partner, and that is what you want to develop on the field, don't be afraid to ask for their view. Hopefully that leadership attitude will work for you.
I once had a game where I was in the C slot and had a sweeping tag play at first on the BR. R1 was on 2B.
I knew I had no good view and I a refuse to "guess" and out. R1 had frozen on 3B we had no other base runner concerns or possible plays.
I immediately pointed to my partner and loudly asked "do you have a tag?"
His answer was immediate and clear, "yes, I do"
I made the call, Batter runner is out.
I trusted my partner becuase I knew he was where he was supposed to be, trailing the BR up the line. He trusted me to go to him.
As a result of that particular call, the two most difficult coaches I had seen that year gave no problems from the rest of the season.
They knew we didn't let ego get in the way of the game, we were on top of our areas of responsibility and we worked together.
We got a lot of compliments from the coaches and spectators as well as league officers.
I know, I know..............if you are going to accept the compliments you have to accept their criticisms too.
But it was nice to hear some appreciation from the folks who saw us working together.