Using VBA to modify Word data - vba

Question

I have a word document. It contains timestamps which I need to modify.
I'm using VBA to modify the timestamps. I been able to find the timestamps. I been able to extract a timestamp and adjust the extracted time in the timestamp. I have not been able to replace the old timestamp.
Question: What VBA do I need to replace the old timestamp?
shouldn't be hard, but I don't know the vba nor word lingo to do a google search.
I'm working with a Word document. I'll provide some plain text so to avoid issues with a raw word document. example text: https://pastebin.com/raw/nf4Cc8bu
Here is the code I have.
Sub FindAndReplace()
'
' vba string functions
' https://learn.microsoft.com/en-us/dotnet/visual-basic/language-reference/functions/string-functions
' https://www.eng.auburn.edu/~tplacek/courses/3600/Strings%20and%20Manipulations.htm
'
Dim c As Range
Dim StartWord As String, EndWord As String
Debug.Print
Debug.Print "start of FindAndReplace() at " & Time() & " on " & Date
Debug.Print "ActiveWindow.Parent (word document name) is " & ActiveWindow.Parent
Debug.Print
Set c = ActiveDocument.Content
c.Find.ClearFormatting
c.Find.Replacement.ClearFormatting
With c.Find
.Text = "[0-9][0-9]:[0-9][0-9]:[0-9][0-9]" ' Time stamp format
.Replacement.Text = ""
.Forward = True
.Wrap = wdFindStop
.Format = False
.MatchCase = False
.MatchWholeWord = False
.MatchWildcards = True
.MatchSoundsLike = False
.MatchAllWordForms = False '
End With
Dim FirstDate As Date ' Declare variables.
Dim IntervalType As String
Dim Number As Integer
Dim message As String
' For how much time do we need to adjust the timestamp so to match the video?
'Number = InputBox("Enter number of seconds")
Number = 45
Debug.Print "Number is " & Number
Debug.Print
IntervalType = "s" ' interval in seconds
c.Find.Execute
While c.Find.Found
Debug.Print "c.Text is " & c.Text
message = DateAdd(IntervalType, Number, c.Text)
Debug.Print "adjusted time stamp is " & Format(message, "hh:mm:ss")
'--> need to replace existing timestamp here.
Debug.Print
' get next timestamp
c.Find.Execute
Wend
Debug.Print "Good bye..."
End Sub