The best option is re-recording the tracks. Getting the take right is always preferable to fixing it in the mix. That said, if the sax and trumpet play on different beats you can use volume automation to both reduce the volume or raise the volume to balance out the instruments. If the sax and trumpet are playing on the same beat, you can use eq to both cut the main sax frequencies and boost the main trumpet frequencies. Keep in mind that you have to be careful not to boost and cut too much as doing so will eventually make your instruments sound unnatural.