1st I am very cautious about not making calls where I should'nt - If I am at the net I do not call the baseline, if I am ad side I do not call the deuce sideline, etc..etc..etc.. -I just feel like my partner has a better view so I simply refuse to make a call on those lines. Considering that, if I am not in the better position to make the call then how can I override my partner?
Do you trust your partner? Do you think your partner is cheating?
If your partner constantly makes bad lines calls and you think there is some cheating I would get a new partner. If your partner just makes bad line calls often because of human error - Well, have a talk prior to your next match and ask what they think you should do when you disagree.