#1 job to amend is DON'T MESS WITH THE INPUT.  

 #2 go to screen 59 and complete everything important. Notice the Amended Return Frequently Asked Questions and click that to get some general instructions. 

At this point the return should look just like the original.

#3 add to or change the original data to what it should be. That will now begin to generate the 1040X and the Schedule AR

Please clarify " I have added the lines that were changed, but Lacerte is not giving me the option to add amounts..."