Notepad would allow you to open the xml file and do a search/replace -- or you could do that with the search/replace function in generalutils.brs before you parse the xml.
Note - string replacement can be extremely slow on roku with a large xml or json file as your source.
from generalutils.brs
'******************************************************
'Replace substrings in a string. Return new string
'******************************************************
Function strReplace(basestr As String,oldsub As String,newsub As String) As String
newstr=""
i=1
While i<=Len(basestr)
x=Instr(i,basestr,oldsub)
If x=0
newstr=newstr+MID(basestr,i)
Exit While
End If
If x>i
newstr=newstr+MID(basestr,i,x-i)
i=x
End If
newstr=newstr+newsub
i=i+Len(oldsub)
End While
Return newstr
End Function
basestr would be rsp, or your downloaded xml prior to parsexml. NewSub would be what you need the tag name to be, oldsub would be what the tag name is now (when you download it)