Renaming a Document Tab 
Renaming a document tab is a page customization that is frequently performed in SAP Sourcing.
Procedure
To rename a document tab:
Choose the tab to be customized.
Choose Reference Guide.
You must have the appropriate rights to access the Reference Guide.
In the Class Reference page for the page element, choose UI View.
Under UI Pages, copy the value in the UI ID column for the document containing the tab to customize.
ExampleFor Projects: projects.projects.ui.buyside.default
End of the example.
NoteAn object can have more than one user interface, with a separate ID assigned to each. For example, there may be one ID for the purchasing side and another for the supplier side. You must create a separate customization record for each UI element that you want to change.
End of the note.Open a new SAP Sourcing window and navigate to
Setup 
System Setup User Interface Page Customization 
.On the Page Customization page, choose Create.
On the Creating: Page Customization page, enter the value you copied from the Class Reference page into the UI ID field.
NoteThis value must be a valid UI metadata ID obtained from the Reference Guide.
End of the note.Under Overrides, choose Add to add an override.
A blank table row appears.
Go to the window displaying the Class Reference page of the Reference Guide and copy the Page ID value for the tab to change.
For example, the Page ID for the Project Header tab is header.
Go to the window displaying the Creating: Page Customization page and, in the Field ID field in the empty table row, enter the value as
tab.<tab Page ID>. ExampleFor the Project Header tab, enter tab.header.
End of the example.Under Property, choose Label.
Enter the new tab name in the Value field.
For example, you might change the Project Header tab name to Overview.
NoteAfter changing this value, you must also create a localized resource and enter its Resource ID value in the Value field. For details, see Creating Localized Resources.
End of the note.Save your entries.