Is it appropriate to use a previous (recent) letter of recommendation for a different application? I have an outstanding letter of recommendation from someone who I am no longer in regular contact with and it would be a hardship to contact them in person (to receive a signed letter). This is the kind of letter that I could run for president on.

I did not receive the scholarship that I originally needed it for.

Contacting the original author is no longer a real option. Is it appropriate to use this letter again for a subsequent application for an unrelated scholarship? (Note that the letter specifically mentions the first scholarship, not the one I am not considering using it for.)

I was considering simply attaching a short note to the front stating the reason for this.

However, something is nagging me in the back of my mind that this seems a little unprofessional. Should I pursue a letter from a different author instead?
I do not think you should reuse the letter as is, for two reasons:


The letter writer did not intend for it to be reused, or else it would have been written more generically.  It's generally not reasonable to use such a letter outside of the circumstances envisioned/authorized by its author.
You would have to explain that there's no realistic way to contact the writer, and that is itself a red flag.  It looks suspicious to say "here's what Professor X would say if you could contact him, but you can't".  A letter isn't worth much if the committee couldn't in principle contact the writer to confirm or ask further question.


Certain rare cases might merit an exception, such as reusing a letter from someone who has since died.  (Where the death is a matter of public record, everybody assumes that of course the writer would have updated the letter if death hadn't intervened, and they are inclined towards flexibility because of the difficult situation.)

How hard would it really be to contact the letter writer?  If it's inconvenient but not impossible, then it could be your best option.