So ambergrain is right as far as increasing the actions in an interaction but I think you wanted interactions per day. The way to do that is to go into the Mansion.gd file and find the advance_day function and change the state.daily_interactions_left to equal the number of interactions you want. This means that every new day the interaction number will be set to your value instead of 1. A couple of important things to note. It will not change the initial value (on day one) you would need to change the value in the gamestate file to do that. It will also show up as x/1 daily interactions left when you look at it in game. The "1" is hard coded in the InteractionSelectionPanel.gd file and can  be changed to match the desired number. Alternatively if your familiar with coding you could create a new variable for max daily interactions and tie both things to it..

Well I was hoping the way to increase them in like game way. Similar to upgrade bedroom to increase participants. But I guess it's not possible. Thank you for your reply.