Merge Rows

On the Mining | Blast Design tab, in the Drillhole Pattern group: Click Merge Rows to merge rows by snapping from the end of one row to the start of another row or vice versa.

You will be prompted to snap from the end of one row ...

... to the end of another row:

The rows are merged:

Merge Rows mode remains active, allowing you to continue to merge more rows. Press ESC to exit Merge Rows mode.

If the results of a merge are not what you expect, use Undo to restore the affected rows.

You can also select an option to Auto Merge Rows. Use the Break Row tool to un-merge those rows: