WELCOME TO THE BOARD!
This macro will do what you are looking for. I wrote it using a CommandButton on the worksheet that you want to change the name:
Dim NewName As String
NewName = InputBox("What would you like the new name to be?", "Enter New Name", "Enter name HERE")
ActiveSheet.Name = NewName
ThisWorkbook.SaveAs Filename:=ThisWorkbook.Path & "" & NewName & ".xls"