A retreat can be an awakening moment, during which some encouraging words would do much. It can be for spiritual reasons, such as to reconnect to a god or it may follow a period in prison. Starting from one day, a retreat takes place in a remote, often isolated place, alone or with a few people. If you decide to send a letter to someone who is in a retreat, you may have experienced it by yourself or want to support the person. For this, you don't have to be a close relative of the person you are writing to.
Write a short and personal letter. Think about supportive words to communicate your sympathy to the retreatant. If you are addressing the letter to a person you don't know, there's no need to put your name or contact information on the letter.
Express your feelings to the retreatant. Write that you are glad he is having such an experience. You can briefly mention your personal experience and how the retreat worked for you.
Reassure the retreatant you will be thinking about her and praying for her, if it is a spiritual retreat. Say something like "As a gesture of love I will pray for you during this Sunday's mass, for the success of your retreat."
State you will be looking forward to the person's return to finish the letter. Sign the letter with your first name.
Write "Dear Sister/Brother" if you address the letter to someone you don't know but who is in a spiritual retreat. Get help from your family to write the letter.