Recognize what makes this moment difficult
Acknowledge the event directly without turning it into a lesson, comparison, prediction, or silver lining. For a message about how to reconnect with an old sports club, use this factual base: name the group, your earlier role, why you left, and the current point of contact you found.
Offer support that can be accepted
Offer one specific form of practical or emotional support and make clear that no immediate reply is needed. Ask whether rejoining or visiting is appropriate and follow the group's present process. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Follow their pace rather than yours
Do not claim an old role, skip current rules, or pressure a volunteer to resolve historic conflict privately. Use safeguarding and formal leadership channels for discrimination, abuse, threats, or vulnerable members. The recipient decides whether they want conversation, ordinary company, practical help, professional support, or quiet.