SSRS - How to change styles of the lines in the Line Chart

1) Open the SSRS report in Report Builder or SSDT
2) Go to the Line Chart

3) Right click on any line over the chart and go to Series Property. You can also right click on chart body and go to Chart Property.

4) Click on Border and change the style according to your requrement e.g. Dotted and click ok.

5) Now, run the report, we can see the Dotted lines in the chart.