This article explains that there is a review process for Local Listing edits that may take up to two weeks.

Each time you make an edit to your listing, we need to review the changes before they show up on the live site. For this reason, we encourage you to make as many edits as you can at the same time.

Usually we are able to process these submissions within 5 business days, however please allow as up to 2 weeks for the edits you've made to appear in Yahoo! Local.