Jesus, as the Good Physician, not only diagnoses the problem. He also advises the path of restoration. His instruction can be summarised as 3Rs. They are to remember, repent and repeat. The first involves the mind as they recalled what they once were like. The second involves the heart because repentance flows from a broken heart. The third reveals a renewed will that delights to practice what is pleasing to God.
The one that is stressed is the middle one of repentance. Perhaps it is stressed because it would be easy to engage in remembering and repeating without repenting. They, and we, could do them without going into the presence of God and expressing our deep sorrow for failure. Yet there is no recovery without repentance. Instead, there will be removal and Jesus will be the One who will bring an unrepentant church to an end.
Jesus then reveals that this letter is not just for the church in Ephesus. He points out that through this letter the Spirit is speaking to all the churches. They may be heading in the direction that Ephesus had gone. Or they may have lost their first love through other reasons. Whatever the circumstances, they were to recover the 3Rs, or else they would be removed out of existence.