You can perform a takeover manually when maintenance is required on the partner, and in other similar situations. Depending on the state of the partner, the command you use to perform the takeover varies.
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Commands for performing and monitoring manual takeovers
You can manually initiate the takeover of a node in an HA pair to perform maintenance on that node while it is still serving the data on its disks, array LUNs, or both to users.
Moving epsilon for certain manually initiated takeovers
You should move epsilon if you expect that any manually initiated takeovers could result in your storage system being one unexpected node failure away from a cluster-wide loss of quorum.