How to ask for a recommendation letter from a professor after long time?
Shouldn't be a big deal.  He will likely just send the same one he has on file.  Send him an email and politely ask for the help.  

Dear Professor Y,

Thanks for your kind letters twice before. I am now a second year Ph.D. student at Fantasy University, working on a thesis in widget design.  It is going well--my training from you and the rest of the ESU staff is being put to use.

I have another request, this time for the SooperDuper Fellowship, which will support me financially at FU.  Actually I have already been shortlisted, so chances are good.  

Could you please send copy of your earlier letter to support me with SooperDuper?  Submission details:


how/where to send
due date


Once again, thanks for your kind help.  Would love to stay in contact.

Sincerely, 

Dukhia