Is this a singing part or a non-singing part? If you're not singing, lean into it - cracking can run the whole gamut of emotions - use it to your advantage! If you're singing, try to keep it in a range you can handle, and be elegant with everything else (phrasing, etc.). As Brian Eno stated - (I am paraphrasing), "Regard your weaknesses as secret strengths". In short, try creatively reframing this to work to your advantage.