After you file
On a 1040X you must provide information on all changes in column B ... so if you have an amount on line 10 the very least you needed to send is the Sch 2. Plus any forms or schedules that were added or changed. 
On a 1040X you must provide information on all changes in column B ... so if you have an amount on line 10 the very least you needed to send is the Sch 2. Plus any forms or schedules that were added or changed.