Deleting charts is not the same as deleting an entire chart file. This topic explains how to delete individual charts from within a chart file.
>> To delete a chart that has been saved in a file
Regardless of whether the chart is currently selected as a chart for either "Chart 1", "Chart 2" or "Chart 3", to delete a chart from the file it's in you need to start in the "Selected Charts" pane. (You can get to that pane by tapping on the Charts tab at the bottom of the screen)
1.Tap on the > at the right of the details panel of any of the selected charts. This will present a list of options for selecting the chart in that position.
2.Tap on the Select from File option. This will either present the "Files" pane showing a list of the chart files on your device, or will open the actual chart file that the selected chart comes from, listing all the charts that it contains (if it's this latter result, you can now skip to step 4).
3.If the "Files" pane is showing on the screen, then tap on the file that contains the chart you want to delete. This will open the chart file, and list all the charts it contains.
4.The filename of the Chart File that has been opened will have a tick next to it. If the number of charts the file contains is more than can be viewed at once, you can scroll up and down the list of charts the file contains by swiping the screen upwards or downwards with your thumb.
5.When the name of the individual chart you want to delete is visible, swipe left on the chart name. A 
button appears to the right of the chart name.
6.Tap on the Delete button. That chart will be permanently deleted from the file.
7.To cancel deleting either swipe right on that same chart, tap on another chart, or on < Files (or < iCloud Files) button in the Charts pane (top left).
