Thank you for the phonecall 

I just wanted to thank you for your call and the time you spent
speaking with me. I have been thinking about the call and I really
feel that I learned a tremendous amount of useful information that
will probably have a significant impact on my career and the choices I
make in the future. The phone call only lasted a few minutes, but its
effects will last a lifetime. You really went above and beyond and I
thank you for answering my questions and for providing your insight
when you did not have to. I hope someday I will have the opportunity
to thank you in person.  I also wanted to thank you for considering me
and I sincerely hope the candidate you select for the open position
will be just who it is you are looking for. I wish you all the best.

Respectfully,