How to Rename Multipage In userforms?

you need somewhere to store your dynamic changes.
why not just use your project sheet name tabs to populate the multipage tabs on initialisation - solves the problem without resorting to saving captions.
leave the multiform page captions blank in the pages properties.
bear in mind that page references are zero based

Private Sub UserForm_Initialize()
Dim x As Integer
For x = 2 To 6
Me.MultiPage1.Pages(x - 2).Caption = Sheets(x).Name
Next x
End Sub