When I chat with two of my friends (say A. and T.), our iPhones use text instead of iMessage. It used to work using iMessage, but one day, it switched to text. A, T and myself otherwise use iMessage with other contacts without any problem. It's only A <-> me and T <-> me which uses text.
How do I reset iMessage in order to re-enable it with these two friends?
Best Answer
You can delete the SMS messages from the conversation and just leave the iMessages. Then reset your phone using the sleep/wake + home buttons. This has restored the default to Send via imessage again for the conversation.