Here are the instructions from the USDA: http://edis.ifas.ufl.edu/he233

Since you're recanning something that was likely canned under pressure the first time, I'd strongly suggest adding ascorbic acid to the fruit and syrup before processing to make sure the fruit is acidic enough to prevent bacterial growth. The heavy syrup will do part of the job but not the whole job.

And as always, if canned anything smells "off," throw it out.