Y'sure can. Here's a link to show you how it's done:

1. The EASY way:

Upgrading Autonomous Cisco Aironet Access Points to Lightweight Mode

www.cisco.com/en/US/docs/wireless/access_point/conversion/lwapp/upgrade/guide/lwapnote.html

2. The CLI way:

Requirements:

• Image file (The recovery file has the prefix “rcv” in the image name, such as c1200-rcvk9w7-tar.122-15.JA.tar);

• AP is connected to the Wireless LAN Controller; and

• AP can ping the TFTP server where the image is located.

Procedure

1. Copy the recovery file to the AP using the following command:

archive tar /x tftp:/// flash:

2. Let the AP boot on this image:

boot system flash://.bin

3. Reboot the AP.

OPTIONAL

• DO NOT ALLOW THE AP TO JOIN THE WIRELESS LAN CONTROLLER.

• IF POSSIBLE, type the following commands:

 clear lwapp private-config (This will bring the AP to factory default.);

 clear lwapp ap ip address

 clear lwapp ap hostname

 clear lwapp ap controller ip address

4. Let the AP connect to the Wireless LAN controller.

OPTIONAL

If an AP refuses to join the Wireless LAN Controller, type the following command from the AP:

lwapp ap controller ip address

Hope this helps.