Add headings to columns in a worksheet through vba

I have the following code. In the "Master" worksheet I want to add columns headings from cells A1 to Z1
how can i do this through vba?

Sub Do_it()
Dim ws As Worksheet, rs As Worksheet
Set ws = Worksheets("Master")
Set rs = Worksheets("Point Estimate Complete")
GoSub Combine
Set rs = Worksheets("Estimates Validated")
GoSub Combine
Set rs = Worksheets("Estimate In Progress")
GoSub Combine
Set rs = Worksheets("Other Status")
GoSub Combine
Exit Sub
Combine:
lr = rs.Range("A65536").End(xlUp).Row - 3
lr2 = ws.Range("A65536").End(xlUp).Row + 1

rs.Range("A3:Z" & lr).Copy

ws.Range("A" & lr2).PasteSpecial Paste:=xlPasteValuesAndNumberFormats, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False

lr3 = ws.Range("A65536").End(xlUp).Row

ws.Range(ws.Cells(lr2, "AA"), ws.Cells(lr3, "AA")) = rs.Name 'd

Return

End Sub