Today I was looking for the ALTER TABLE EXCHANGE PARTITION feature for a customer, and it looks like it did not get included into MySQL 5.5, although there is a hint of it in the documentation index, and you can find quite a few blog posts and presentations about it. The command simply throws a syntax error:
alter table t exchange partition p1 with table t2;
The worklog is still open, although a related bug report it mentions is closed and pushed into trunk. (It confused me for a moment until I realized that what was pushed into trunk, and released in 5.5, was TRUNCATE PARTITION support.)
Here’s hoping this gets included in a future release—this is a great feature that can make partitions much more amenable to operational tasks such as moving data from one partitioned table to another, or exporting a partition to a table, then exporting the table with xtrabackup and importing it onto another server.