Hi!
I had a similar concern with you about this problem when I transferred. It is important that you show your friends that you want to still keep in touch with them after graduation like keep texting them as before or tell them. So that they will also pay more attention to responding back to your message or think of you when they want to find someone to talk to. You can also share interesting things you see or talk about things in your school or ask them. Greetings on holidays or birthdays is a good way to keep contact as well. However, I think all these above based on if both of you want to keep in touch after graduation, it happens and don’t push them hard.
I hope this helps!
Dear Letterbox
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