How do you make a last name that ends in an s possessive?

There are two accepted forms for possessive singular nouns that end with an s:

Add an apostrophe (') after the existing s at the end of the Word:

• Jones'

Add an apostrophe s ('s) after the existing s at the end of the Word:

• Jones's

Examples:

The meeting is in Mr. Jones' office.

The meeting is in Mr. Jones's office.