This 'potential work opportunity' is a can of worms.
Sure you can take the order if you comply with all the guidelines, including the ML letters relating to this.
http://portal.HUD.gov/hudportal/HUD?src=/program_offices/administration/hudclips/letters/mortgagee
Read all the documentation about this. It's somewhat straightforward and there are a few key ML's about this.
Will your final be by attachment, or by reference? HUD requires one not the other.
You don't really believe that BS about the appraiser being on vacation for 3 months do you? Maybe he refused the order due to inadequate fee... You sign off on a 1004d by attachment, which means you've now supported the value conclusion and passed the original appraisal because you've provided additional documents, signature, and whole report verification which ride along with the original.
Probably better left for partner appraisers and such, not so great for pick me up work for total strangers, but you can do it if you want to. Sounds like a review, a final, and something near a supervisory signature.
But let me ask you, if you're going to do all that work, why not just sell them on a whole appraisal?
1004D's for work I've already completed are $100-$200 depending. I never follow up another appraisers work. I tell them they should have used me for the initial report, then they would not be having issues like this.
Another wonderful AMC thread.