Interoperability with existing timebanks is both a social and technical challenge. Most conventional timebanks already operate as mutual credit systems based on hours, trust, and local governance. This makes them philosophically compatible with the Intergalactic Timebank, even if their technical infrastructure is very different. The aim is not to replace existing systems abruptly, but to offer a gradual, respectful migration path. For an individual member moving from an existing timebank, the simplest approach is recognition rather than conversion. A member can import their participation history as an attested record, endorsed by their original timebank or by peers. This attestation can be issued as a certificate NFT linked to their towel identity, granting an initial credit limit or reputation score without directly transferring balances. In this way, past contribution is honoured without forcing incompatible accounting systems to merge. When an entire timebank wishes to switch over, the process resembles a constitutional migration rather than a technical upgrade. The group can snapshot its current ledger, governance rules, and member agreements, then collectively adopt the new system. Initial Voz balances can be issued as opening credits based on the snapshot, while pledges and roles are re-expressed through the Pledge Bank and certificate system. This allows continuity of trust while moving to a more transparent and federated infrastructure. Conventional timebanks may raise several concerns. Some will worry about complexity, especially the introduction of digital identities, signatures, and NFTs. Others may resist the idea of negative balances or explicit credit limits, preferring informal social enforcement. There may also be cultural resistance to publishing data, even in anonymised or federated form, and concerns about excluding members who are less digitally confident. These issues are addressed through design choices. The system can operate in a very simple mode, where Voz behaves exactly like hours and the interface hides most cryptographic detail. Governance remains local, and federation is optional. Crucially, the system does not introduce markets or speculation, which reassures communities that their values are preserved. The promise is not efficiency for its own sake, but durability, portability, and shared learning across timebank cultures. In Hitchhiker terms, interoperability is about hospitality. The Intergalactic Timebank does not demand that travellers abandon their old customs at the airlock. It provides translation, recognition, and time to adapt. Over time, communities adopt the new system not because they must, but because it helps them tell their story, keep their promises, and travel further together.