Switching 24V and GND with MOSFETs
The part you chose, IR21844 is a half-bridge driver, so it's designed to work in only one direction (polarity).  It's also not specifically designed as a motor drive.  Depending on your actuator, it may or may not be suitable.  The easy answer would be to use a full H-bridge driver that can handle polarity reversal for you, such the L6201. That will save parts, time, and headaches.

If you can't change parts for some reason, you'll need to an extra set of MOSFETs controlled by the microcontroller to provide the remainder of the H-bridge circuit.  Have a look at the block diagram for L6201 to get an idea of how to wire up the MOSFETs.

On a minor note, your schematic is backwards.  Usually people draw them with inputs (DIR) on the left, and outputs on the right.