Looking for assistance with VBA macro code.

I have more than 3K XML files for which unique identifiers need to be replaced with others. There are three components to this:
  1. a reference excel file, or "data-source" (see below) with one worksheet (Main) that includes the unique ID in each of the XML files and the corresponding ID (with appropriate column headings) that needs to replace the value that is in the XML file.
  2. a second excel file that that includes a cell to reference the directory and file-name of the data-source file, another cell to include the directory only of where the XML files are located, and obviously the VBA macro code is embedded within this file with a button on the spreadsheet.
  3. and the actual XML files the need to be modified that are named with "Case Tracking ID" from below included in the file-name, and the list of files in that named directory sorted alpha-numeric.
    1. 220086OPPMPM38927_1125644933111.xml


I have done some work with this, but it's either replacing each value in XML files with the same value (the one that's first in the data-source list), or it simply deletes the value in XML files without replacing it. As far as I can tell, the VBA code is missing the code in the "GetPatientID" function (see below) to "loop" through the data-source until "EOF" is reached. I've tried to modify it to include that, but I'm not getting it to work.



data-source: Master.xlsx
Case Tracking ID
 EOC ID
PM38927
 1388670
PM38928
 2608904
A0711291600004
 0711291600004


Replace tags in XML.xlsm
H:\Data_Analysis\PatientIDReplace\XMLFiles\
H:\Data_Analysis\PatientIDReplace\Master.xlsx
 
 Function GetPatientID(ByVal PatientID As String) As String
    Master.Activate
    What = Cells.Find(What:=PatientID, After:=ActiveCell, LookIn:=xlFormulas, _
        LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, _
        MatchCase:=False, SearchFormat:=False).Activate
    Range("B2").Select
    For i = 1 To 10000
       MatchCell = "A" + Trim(Str(i))
        RawCell = "B" + Trim(Str(i))
        If Range(MatchCell).Text = Range(RawCell).Text Then
            GetPatientID = Range(RawCell).Text
            Exit For
        End If
    Next
   
End Function



Thank you.