Problem with splitting line

[ManuelBerger]

Hi everybody!

I have a problem with splitting a certain line. The message "Select a single editable line to split" appears even though I have selected the line correctly in the editor toolbar. Said line is a former polygon (of a state border) so it has no start or end point. Could this cause the problem?
In fact, at the point where the line should be cut, I want to continue with another line (the final goal is to produce a new polygon out of various segments of lines) so I also tried to trim the first line but that didn't work out either. Maybe there's also a much easier way to reach my goal. I'm rather a newbie with this kind of editing features.

I'm attaching a word file including a screenshot for better understanding.

Thanks for any help!
Manuel

[JuanLuera]

Hola Manuel,

In reviewing the Word document you provided and going through your posting. I would suggest for you to double click the line of interest, this will reflect the certices. At the location where you want to split your line, you want to hover over the line or vertice, and then use the Split Line tool. This will split the line at that location, and then you can delete the line not needed. Please let us know if you have any further issues. Gracias, Manuel!

[JoshThompson1]

Manuel,

The message "Select a single editable line to split" might suggest that more than one feature has been selected.  (It's possible that there is another feature selected, perhaps on another layer which is turned off and not currently displayed.)  Verify that prior to using the "Split" tool that only one and only one feature is selected.

Josh