Every digital image has a specific size: the width and height in pixels. The amount of information depends on that.

In digital image files, the number of pixels per inch is just a hint. It indicates a proportion that should be used for calculating the actual size of the image when printed.

If you have an image of 1000x1000 pixels and you print it at 100ppi, the final size in paper will be 10x10 inches. If you print the same image at 10ppi, the size will be 100x100 inches.

Simply changing the ppi (or dpi) field doesn't really add/remove pixel data. Your software should not delete any detail when changing from 72ppi to 300ppi. Similarly, it can't add detail.

If your software allows you to change the ppi without changing the final print size, then it surely does it by adding/removing pixels. It might add pixels by interpolation, which doesn't really add detail, but helps to avoid the big squares (pixels) that you see in badly magnified digital images.

To summarize, if you want to get image details out of nowhere by twiddling with the ppi field, the answer is: "No, you can't"

On the other hand, if you want to print a low-resolution image in a big size, you can increase the resolution by adding interpolated pixels, and then print in high ppi. This way you will avoid the ugly big squares. That said, any modern equipment should do that for you when printing in low ppi.