What is the monastic policy on family visitations? If one was to ordain, would they ever be able to see their friends and family again? If so, how often? Thank you
If one was to ordain, would they ever be able to see their friends and family again?


The following quote is from the book "The Bhikkhus' Rules
A Guide for Laypeople", Chapter: Intimacy - Touching. The last part of the paragraph is interesting. I have highlighted it:


  "If a bhikkhu touches his mother out of affection, then this is still an offence but the lesser one of wrong-doing (dukka.ta). [46] While gratitude to parents was strongly emphasized by the Buddha, the bhikkhu having left the home-life and his family should not cling to worldly relationships. The only true way for him to fulfill his filial obligations is by gaining insight into Dhamma and then teaching his parents."


Here it's stated that if possible one should teach the Dhamma to ones parents, meaning that one will be able to see them again.

There is another quote from the same book, Chapter: Rains Retreat:


  A bhikkhu must make a formal determination to be resident at dawn every day in that place for the whole three month period. (There are exceptional circumstances when he may be allowed to be away, but even then he should return within seven days.)[26] These three months are often a special time of study or meditation and so are sometimes known as the Rains Retreat or Rains Residence. This is also the normal time when the young men of South East Asia become monks for the traditional three month period.
  
  [26]: This special leave of absence (sattaaha) can only be taken in order to: visit or nurse ill Dhamma-friends and parents; support fellow bhikkhus who are thinking of disrobing; to attend to some essential duty of the Community; to support faithful lay devotees who make an invitation. (See EV,II,pp.84; 89-90)


Here it's mentioned that a monk is allowed to take leave from the Rain Retreat only under special circumstances, e.g. to visit or nurse ill parents. One should return in seven days.


  If so, how often?


I could not find anything within the Theravada Tradition as to how often one is allowed to visit family.

Here is a quote from Plum Village (Zen Buddhism):


  When you are ordained as a monk or a nun, you make a commitment to stay with the Plum Village Sangha for the rest of your life.  The Sangha is your family and our monasteries are your home.  Even when difficulties arise, we do our best to live in harmony with our brothers and sisters.
  
  Your immediate family is welcome to visit you and they do not have to contribute to expenses. You can also have leave to visit your family every two years, or, in the case of an emergency, sooner.