expand (something) into (something)
1. To become larger or more extensive. Don't pull the cord on that, or it will expand into a raft!
2. To make something larger or more extensive. In this usage, a noun or pronoun is used between "expand" and "into." Don't expand that into a raft just yet—wait till we get to the lake. The publisher wants me to expand my short story into a novella.
expand something into something
to enlarge something into something; to make something grow into something. She expanded her business into a national company. I would like to build on an addition to expand this room into a more usable space.
expand into something
to grow into something; to enlarge into something. The little problem expanded into a big one in no time at all. In no time at all, the vegetable garden had expanded into a small farm.