Please set “Block User” or “Unblock” in the three-point leader of the history detail screen. If the user is initially blocked or not blocked, “Block user” will be displayed, and if the user is blocked, “Unblock” will be displayed.

If you have blocked the other party, you will not be able to send outgoing messages or send messages. Similarly, if the other party has blocked you, you will not be able to make a call or send a message.
A message to that effect will be displayed on the screen.