There is not a remove option.
You can deploy a different form.
Or I guess you could set the two files back to default or you could delete them maybe.
Both files are in the ldclient directory.
The default data inside LDCustom.ini is as follows:
The LDCustom.dat is blank by default.
When you create a new data form, by default it deletes the old one. (You can edit it in "Manage Scripts")
The command to delete the old one is:
So you could create a new custom script with the above and deploy it.
When a new custom form is created, .frm entry will be created under LDLogon and LDlogon\cache directory in LANDesk server.
Delete these .frm files and the entries in agent configuration settings will be deleted.