I haven't seen a way to go back to a previously offered cog. I have noticed, though, that if you keep going for awhile, you will notice a finite number of features that appear in various combinations. For example, as we were rejecting cog after cog, my daughter noticed that there was a leopard-like fur that she wanted her cog to have. She also wanted a certain type of ears, so we just kept going until we got the combination she was looking for. You can use the "window shopping" time to check out what the variations are (fur color, ear type, etc.!) It might take a little while, but you can get exactly what you want that way.