Tutorial: How to convert spline into a lines and arcs?
Another option but in this case I will convert randomly shape splines
1. Click EDIT - TRIM/BREAK - BREAK MANY PIECES
2. Select spline entities, Press enter
3. In Ribbon Bar you need to select Button definitions Curves and Tolerances Tolerance this field specifies the chord height tolerance you want to use when breaking an arc or spline. Chord height tolerance (distance) determines how closely the resulting segments fit the original entity. A smaller value results in a closer fit. A larger value results in a looser fit.
4. You can also use Delete / Keep / Blank
Delete the original geometry
Keep the original geometry
Blank (hide) the original geometry.
And then press enter or click ok. if you are done