Assuming you don't need to support multiple date formats, you can use a Substitution process to do what you're asking.  Or you could capture each part of the date as a separate token and recombine them in any order in an Assign Token Value process.  Also, just something to be aware of is that token formatting supports date/time formatting.  It won't help with parsing the yyyymmdd format, but could help when reformatting the date/time (e.g., if you wanted to drop leading zeroes on the month and day or change to a 2-digit year).