It seems like you get different answers for this question from different appraisers and different financials.
I have seen it done many ways, but as the original financial purchased the report from the appraiser, it stands to reason that you cannot use it without authorization from both parties.
How we handle it is to approach the other financial and the appraiser to request the use of the report from both. Then the appraiser will re-do the report and generally charge a nominal fee (often around $100). The justfification behind this is that they are to review the report and update it for any changes or new comps available since the original completion, then note that they have previously appraised the property on the applicable date and briefly summarize any changes (or lack thereof) since the original report.
Because it is updated and reviewed, it is not simply a re-addressed report. We have been fortunate in that the very few times this has happened, it has been an appraiser that is also on our approved list. If it were an appraiser we were not familiar with, we have in our policy that we would have to obtain a new report.
Someone's about to get horned!