Never impose yourself on the judgment aspects of your partner's call---even if it is an obviously poor judgment causing a blown call. It's his call, and his argument.
However, if there is an aspect of the play that you believe he may not have seen that led to that blown call---such as a ball dropping from a glove during a tag attempt, then approach him after the play to ascertain he is aware of that information.
Bill, are you aware F5 dropped the ball?
If he says yes, then leave him alone. He made his judgment decision having knowledge of that fact.
If he says no, then he is now aware of the information you have provided and can change his call if he so desires. He may ask you further questions regarding the timing of the drop, etc. Add the information, but the decision remains his, not yours.
You should also approach your partner if you feel a rule interpretation has been misapplied. Suppose F1 attempts a pickoff throw
after stepping back off the rubber, and the ball goes to DBT. Your partner awards only one base for the overthrow. Approach him to ascertain that he is aware a throw from off the rubber is a 2 base award. The decision of the reward still remains his.
Usually you won't have a long opportunity to present this added information because a complaining coach will be at your partner first. Work your way toward your partner slowly, but do not impose yourself into his argument. Your presence let's your partner know you are there if he needs you. Many veteran officials can read the body language of their partner and realize he has something he wants to tell you. Take the time to talk to him if needed. It frequently may resolve the issue.
But remember,
never attempt to overrule your partner.
Just my opinion,
Freix