You can write a procedure in VBA. Important objects for you to use are DAO.Database, DAO.QueryDef, the SQL method and maybe Replace(). Example:
Dim Db As DAO.Database
Dim Qdf As DAO.QueryDef
Dim strSQL As String
Set Db = CurrentDb
For Each Qdf In Db.QueryDefs
Qdf.SQL = Replace(Qdf.SQL, "Old Text", "New Text")
Next Qdf
Set Qdf = Nothing
Set Db = Nothing
Be careful with tools like that, as the syntax of your SQL statement fully depends on your replace statement. Access will throw errors in case the syntax isn't correct.