PepperdotNet - As mentioned in the article we get better performance inside the OS without LACP so SET does not support LACP.
Using LACP requires special configuration on the switch. Not using LACP does not require any special configuration. Therefore, if your ports are already in a port-channel, you just need to unconfigure your switchports from the port-channel.
Since this will immediately break the teaming functionality you have in the OS (LBFO did support LACP), the tool will not allow you to move forward (we didn't someone to accidentally cause an outage). However, you could try the -AllowOutage param and see if that lets you work through this (I personally don't know if this works but you will still need to break the port-channel on the switch first).
If you run into trouble, please contact support.