If you choose Option 1, your report would be a complete package--as if you had never seen the property before, do at least completely new exterior observation of the property (form 2055) or also interior (form 1004), photos, measurements, etc, provide all the exhibits that you would normally provide, etc, etc, etc. It is a completely new appraisal assignment and a completely new report.
If you choose Option 2, you could use either a 1004 or a 2055, clone your old report, leave the info from the cloned report in that you want to retain or maybe write see original report that is being incorporated and then attach all the pages of the original report (even if you decide to leave the cloned info in the blanks). A new assignment, partially new report, at least drive by the property if you decide on using a 2055, new interior if you decide on the 1004, etc. It is also a new appraisal--steps in report are different.
If you choose Option 3, and the client is the original lender and you are the original appraiser or appraiser firm, everyone involved has copies of the original report. Then you could write a letter that has the seven required items, incorporate the in the letter by reference the original report every one has, attach a market grid with new data (Section 201-knowledge of current market conditions), at least drive by the subject (Section 201 - based on his or her exterior inspection of the property), what ever exhibits would be needed for the new information and a limiting conditions as required in Standards Rule 2-3. You are still doing a new appraisal--just reporting in a different format.
When a lender orders a "recert", you are doing an appraisal (by the way, you always have been) and it has to be in compliance with Standard 1 Development (AO-3 Development Requirements) and Standard 2 Reporting (AO-3 Reporting Requirements).