Yes, at both granularities: individual facts can be forgotten with the reason on record, and tenant deletion removes your company's platform state, with any retention exceptions documented rather than silent.
Fact-level: you or the API can retire specific memories, auditable. Tenant-level: leaving Heidi means your storage, logs, checkpoints, and volumes are removed or provably orphaned.
Deletion you cannot verify is a promise, not a feature. Heidi treats it as a feature.