Had a musician forward me an audio trumpet track he laid down for me for a chart I wrote. He made a slight goof which instead of sustaining a note he staccato it. Any editing tricks anyone knows and wants to share with me so that I can stretch the note? 

I suspect the tonal quality of a staccato note is different enough from a sustained one to sound wrong if you tried to stretch it.
 
So if he's played the same note somewhere else on the track, split the clip around that note, copy it, and paste it over the staccato one.
 
Otherwise, take a note close to it and do the same but also pitch shift the note.
 

what msmcleod said.
 

Also, if the above solution doesn't work, maybe there's a way of overdubbing a trumpet sample for just that one note to patch it up ? 

LOL! Thanks guys. It was right in front of my face all along....Found that same note sustained elsewhere. Copied, pasted, matched the levels and BAM! Problem solved, (just like you cats said). It's all about editing skills...