After you completed at least one route in the game and you go back to the main lobby before you choose the original story, you can see that something new is unlocked which is 'Extra'. There you can find and reply:
Chat historyIn chat history, the player can replay the chat conversations in every route they've had. The player has to choose one route and scroll through the days to reply every chat they had there. However, replies that have been said can't be changed in these chats. The player can also search through "common route 01" and "common route 02" to see the chats in the prologue and in the first day. The player can't view chats that haven't happened yet.
Phone historyIn phone history, the player can replay the call conversations in every route they've had. The player has to choose one route and scroll through the days to reply to every phone call they've had there. The replies in the phone calls cant be changed. The player can view 'common route 01' and 'common route 02's phone calls and hear the conversations in the first day. If the player doesn't have a route or has missed phone calls, those calls can't be viewed.
In the album, the player can see all the pictures that have been sent to them. The player can't see pictures that they haven't received yet.
The player can see all the guests they've convinced to come to the party via guest list. Guests that do not attend can't be seen in the guest list.