Can I do PRP 2 weeks apart just once? I have a trip and that works great for me

Although this most likely does not adhere to most providers PRP schedules, it will unlikely cause any harm or problem with hair loss.  I generally recommend treatments 6 weeks apart for a series of 3 treatments.  If treatments are spaced closer together (2 weeks) I am not sure if the treatments will still have the same timeline for success. 
Not everyone is a good candidate for this treatment so please see a Board Certified or Board Eligible Plastic Surgeon to evaluate if you may benefit. Good luck!
This content is for educational and informational purposes only. It is not a substitute for medical advice, diagnosis, or treatment provided by a qualified healthcare professional.  You should always seek the advice of your physician or healthcare professional for any questions you have about your own medical condition. 

We perform PRP SC for hair growth and results are promising It would be reasonable to shorten the interval between treatments. Best, Dr. KaramanoukianLos Angeles

I have a very specific protocol, every 3-4 weeks for 6 months with photography.  I also add in progesterone to speed the healing process.  After that the injectors are tailored down.  You should also be on viviscal and other growth promoting ingredients.  Best, Dr. Emer.