Note, there are some metals that cannot be resized:

-Tungsten Carbide

-Titanium

-Stainless Steel

Traditional metals like platinum, gold and sterling silver can typically be made larger or smaller by one or two sizes. This process must be done by a professional jeweler with the skills and tools to make the alterations. Cost will generally correlate with the expense of the metal itself. For instance, platinum is more expensive and will generally carry a higher price to resize. Another potential increase to cost is if your ring features gems or a specific setting. The process may be more intricate depending on these factors.

Work with your jeweler to figure out what your best options for resizing are.