On your account, a contact can be in one active or paused drip campaign at a time. Start a second campaign that includes someone already mid-flight in another, and they are skipped from the new one.
#Why
Two sequences running at one person means two unrelated stories arriving at once, at a pace neither campaign intended. It reads as carelessness, and given the daily cap, it also means messages get dropped rather than delayed. The rule prevents the situation instead of managing it.
#What counts as occupied
| Campaign state | Contact is |
|---|---|
| Active | Occupied |
| Paused | Still occupied, pausing does not release anyone |
| Paused 14+ days | Released automatically, and free to enrol elsewhere |
| Completed | Free, but not moved anywhere automatically |
| Draft | Not occupied |
A paused campaign still holds its contacts. If you pause one campaign to run another at the same people, the second will skip them. After 14 days of pause they are released automatically, but that is a safety net, not a workflow.
#The overlap warning
If any selected contacts are already enrolled elsewhere, a warning appears when you click Start, listing each person, their email, the campaign they are in, and the step they are on. You choose:
| Option | Effect |
|---|---|
| Cancel | Nothing starts. Go and rethink |
| Continue without them | The campaign starts for everyone else; the overlapping contacts stay where they are |
| Move them into this campaign | They leave the old campaign and join this one |
You cannot place one contact in two active drips. That is intentional, not a missing feature, no combination of options produces it.
#What completion does not do
When a campaign finishes, its contacts are not moved on to anything. They are simply free. If you want a follow-on sequence, add them to it explicitly.
#What to do instead of two campaigns
Almost every case where people want two campaigns at one audience is better served by one campaign with more steps. An invitation and a reminder are step 1 and step 2 with a delay between them, not two campaigns racing each other.
The worked example is Running an event series safely.