on the Members tab of the ribbon, or from the member menu select Expand member to. Choose the level to which you want to drill up or down.While drilling up and down a member enables you to expand and collapse it one level at a time, the Expand Member option allows you to expand or collapse the member to any level with a single click.
The Collapse <member> option collapses an expanded member to the first level.
To show a member level:
Click on the member heading and click Expand to Level on the Members tab of the ribbon, or from the member menu select Expand member to. Choose the level to which you want to drill up or down.
Example
The example below shows the Clothing member drilled down to the Subcategories level.
Hovering the pointer over a member displays a tooltip with all the levels above that level.
To collapse a member to level one:
Click 
in the member heading and from the member menu select Collapse member.