Squeeze some more lines on the current page

Use \enlargethispage or \enlargethispage*

According to the documentation,

\enlargethispage{size}

\enlargethispage*{size}

Enlarge the \textheight for the current page by the specified amount; e.g. \enlargethispage{\baselineskip} will allow one additional line.

The starred form tries to squeeze the material together on the page as much as possible. This is normally used together with an explicit \pagebreak.

Well for two lines, you should not change too much, but the one line (also called widow or widowed line) should be avoided (also the single line of a starting paragraph at the end of a page - called orphan). So instead of doing it manually for a single page, which you would have to change if you add a new word or sentence, you could tell TeX to avoid widows and orphans by adding

\clubpenalty = 10000
\widowpenalty = 10000
\displaywidowpenalty = 10000

That would not avoid the two lines on a seperate page, because that is still okay in typographical philosophy, but at least the one line.

You can change the margins of the page just for this page:

\usepackage{geometry}
...
... 
...
\newgeometry{top=0.5cm, bottom=0.5cm}
...
... <The enlarged page contents>
...    
\restoregeometry %so it does not affect the rest of the pages.
...
... 
...

For more detailed answer look at this.