Type `LINETYPE` or `LT` and press Enter
Click `Load`
Select a dotted or dashed linetype such as `DASHED`, `HIDDEN`, or `DOT`
Click `OK`
Select the line
Open `Properties`
Set `Linetype` to the dotted linetype
If the line still appears solid, type `LTSCALE` and adjust the value
Type `REGEN` and press Enter
If needed, set `CELTSCALE` before drawing new lines
Draw a new line using the selected dotted linetype