I am having trouble replacing a part in a part structure?The replace managements tab opens and when i select the part to be replaced and click OK it does not do anything

[jfrancis]

The replace managements tab opens and when i select the part to be replaced in 'alternates' and click OK it does not do anything

[SvenVanDroogenb]

What you are describing is the use of Variants (Alternates and Substitutes).

If you want to replace a WTPart in a Structure, you will need to use Remove and Insert Existing or Insert New.

There is no Replace functionality available in the Structure tab.  You can use a Replace function in a Change Activity.