\enlargethispage

Synopsis, one of:

\enlargethispage{size}
\enlargethispage*{size}

Enlarge the \textheight for the current page. The required argument size must be a rigid length (see Lengths). It may be positive or negative. This command is fragile (see \protect).

A common strategy is to wait until you have the final text of a document, and then pass through it tweaking line and page breaks. This command allows you some page size leeway.

This will allow one extra line on the current page.

\enlargethispage{\baselineskip}

The starred form \enlargesthispage* tries to squeeze the material together on the page as much as possible, for the common use case of getting one more line on the page. This is often used together with an explicit \pagebreak.