You can control a sequence at two levels.
Pause a single contact's progress (with a reason) and resume it later. This is useful when one person needs to be held back without affecting everyone else.
Pause the entire sequence to stop all sending, then resume when you're ready. Archive a sequence you're finished with — any in-flight enrollments finish gracefully rather than being cut off.
To reuse a sequence's structure as a starting point for a new one, clone it. That copies the steps so you can adapt them instead of rebuilding from scratch.