You may also like to read about BIML - a modelling language that can be 'built' into an SSIS package from within BIDS Helper (which is free). We use it here and can regenerate lots of packages in seconds (v useful in a warehousing environment if you have lots of packages doing essentially the same thing, just for different tables).
If you haven't even tried to resolve your issue, please don't expect the hard-working volunteers here to waste their time providing links to answers which you could easily have found yourself.