Form 1040 Schedule 1 Line 18, how to clear it?

[BoatMan0]

Upon "Federal Review" an error was flagged and it showed me Form 1040 Schedule 1 and only Line 18 was editable.  I entered the value the error indicated just to placate the checker (knowing full well the value in the indicated field was incorrect but assuming I could "go back later" and correct it).  Here I am, needing to get back in and edit Form 1040 Schedule 1 Line 18 but can't.

I've checked all of my HSA work, IRA contribution activity, and 1099-DIV/1099-INT numbers, none seem to correspond to the number appearing on line 18.  A hack would be to enter Form 1040 Schedule 1 Line 24z to "reverse" this number (enter a negative value) so that they zero out, but I can't even find a way to enter Income Adjustments to do this.

So, Form 1040 Schedule 1 Line 18 has a value in it that I would like to zero out.  How do I get to a screen that allows me to do this (Turbotax online)? 

Thank you very much.

[BoatMan0]

2 hours total but RESOLVED!  TT Level 1 product support was unable to assist but then the escalation team was able to walk me through identifying, deleting, and reentering the problematic K-1 and subsequent "Review Error" that was generated.  Likewise, they also noted TT screen errors (not user errors) through the process and were able to screenshot those for add'l follow up.

Thank you very much.