If your NCR is in planned status, you can Delete it (with the Delete button).
But once you Release it (Released for Disposition) you can’t delete the NCR. Because, the option of “Released for Disposition” creates a Disposition Line.
However, at any stage for the Disposition Line (Release, Dispositioned, Corrected, Verified) you can reverse the status to the previous and finally cancel both the Disposition Line and NCR.
If it needs to be a button like in a form you are likely looking at a customisation.
but you could also create a custom menu (right click).
this could include a check against whichever permission set is required first and then proceed to find any disposition lines, revert them to planned, remove them and the proceed to remove the ncr.
You can add a custom field to delete by providing the SQL which is the simpler option. Or else you could go for a customization.
More Feedback on the Topic- Some of the customers use the cancel option currently, as a delete button is not available.
The issue is that, customers generate statistical reports based on the canceled NCR. (Number of canceled NCR) Hence, canceling such NCR will be incorrect in that sense. The best option would be to go for a customization which would be the best solution.
Another option as mentioned, would be a custom field. However, my personal view would be a customization since that would be less complex.