Yes, you can. Simply open a helpdesk ticket in our support system and let the staff know you want a full license. They will invoice you for the full price minus one month lease payment and switch your license file.
You will have to download your new license file and upload to the site, but all other files and data will remain in tact.

If you are leasing from an AWBS Authorized Reseller, please contact them for their billing policy to switch your license.