From the Paragraph panel menu, choose Kinsoku Shori Type and then choose one of the following methods:

Push In First

Moves characters up to the previous line to prevent prohibited characters from ending or beginning a line.

Push Out First

Moves characters down to the next line to prevent prohibited characters from ending or beginning a line.

Push Out Only

Always moves characters down to the next line to prevent prohibited characters from ending or beginning a line. A push in is not attempted.

A check mark indicates which method is selected.