To change the Lead-In point within a contour toolpath in CAMWorks you have a few options to choose from.
To find these settings you will need to open your Operation Parameters for the contour toolpath you are working on. Navigate to the Lead-in tab.
Within the lead-in tab, you will find the "Leadin/out point" section which is where you set your start point. The first option is the Mid-point. This is selected by default and chooses a mid-point on a segment of the feature, shown as a blue dot. You can select other segments on the feature by clicking on the edge of the part in the active solidworks window. You will see the blue dot move when selecting other segments.
The second options is Start-point. This is where you will direct the the start point location. When choosing this option, the blue dot indicating the start point will move to the start of the segment. To give the start point another location on that segment you can use the offset options that have become available in the window. Move the arrows or type in an offset amount to indicate a new start point, or select the percentage button and move by percent. You can also choose another line segment by selecting an edge on the part in the active SOLIDWORKS window. The start point will move to the end of that line selected.