craftgrrl | question about selling products made from patterns

Is it breaking copyright to make something (ie: crochet a stuffed animal) from a pattern and sell the actual item? If the pattern is modified slightly, or the name of the item changed, does that break copyright?

I'm just wondering since I sell my own crochet stuff on my site, but I have a couple of items that I've made from patterns & have no use for and would like to sell online, perhaps so someone else can use them instead.

I figure as long as I don't claim that the pattern of the item or the design of it is my own and give credit to the author, then I should be ok.. yes? no?

Thanks for answering. :)