Why were the 76ers and Raptors able to make a trade while the finals is still on-going?

are you allowed to make trades already when your team stops playing (like when they dont make the playoffs or when they get eliminated) or is it ok to trade again when it's already finals? it isnt off-season yet right? i know reggie and jason have to p physicals first so it isnt official yet but they still made the trade.