# ClusterMembershipSnapshot.CreateUpdate(ClusterMembershipSnapshot)

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.runtime/orleans.runtime.clustermembershipsnapshot/) | [Methods](/orleans/docs/api/csharp/microsoft.orleans.runtime/orleans.runtime.clustermembershipsnapshot/methods/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Runtime/MembershipService/ClusterMembershipSnapshot.cs#L88-L118)

```csharp
public ClusterMembershipUpdate CreateUpdate(ClusterMembershipSnapshot previous)
```

Returns a [ClusterMembershipUpdate](/orleans/docs/api/csharp/microsoft.orleans.runtime/orleans.runtime.clustermembershipupdate/) which represents the change in cluster membership from the provided snapshot to this instance.

### Parameters

- `previous` (`ClusterMembershipSnapshot`)

### Returns

A [ClusterMembershipUpdate](/orleans/docs/api/csharp/microsoft.orleans.runtime/orleans.runtime.clustermembershipupdate/) which represents the change in cluster membership from the provided snapshot to this instance.