The FL Dept. Of FInancial Services States on their site:
"If an individual holds a general lines agent license and wish to add or convert over to an adjuster, you must apply online and submit the fees of $55. (No examination is required"
Basically, a 2-20 agent can switch the license to an all lines adjuster license, and switch back.
The 4-40 license is a customer service representative license, and that cannot be switched over to an adjuster license.