I find it depends on who you speak to, especially their maturity.
Generally, just say you'd like to catch up or meet again. Talk about it, what each of you would like to do. make plans. with certain people (e.g. you're a man and they're a woman), you can say "as friends" to indicate you are not looking for anything more, if you desire that. It's useful to say if they seem to think you want a relationship.
I find that people who feel weird when you say you "want a friendship" or want to do something "as friends", have had fake-friends, had a relationship with a friend, or have found people who say they want to be friends to be odd or harmful.
Showing you want friendship, with NTs, is not in saying you want one, but in your actions, behaviour that shows you're sociable and friendly.
_________________
Life is Painful. Suffering is Optional. Keep your face to the Sun and never see your Shadow.