To move someone to a new date, stop the current enrollment and re-enroll them manually against the new one.
Messages that have already been delivered stay delivered. This process controls what happens from here, so part of the job is telling Pyn not to send those again.
Before you start
Have the new start date to hand, and know roughly which messages the person has already received. You will need that in the last step.
Step 1: Stop the current enrollment
Go to Activity > Enrollments > All Enrollments and click on the enrolled person. In the panel that opens, click the three dots in the top right and select Stop.
This cancels every message still scheduled for that enrollment. Anything already sent is unaffected.
Step 2: Start a manual enrollment
Open the flow, click the Manual dropdown at the top, and select Manual Enroll.
Step 3: Set the new start date and enroll the person
On the manual enrollment screen:
Set Reference Date to the new start date.
Turn on Verify Mode. This holds the enrollment so you can review the messages before any of them go out, which is what lets you exclude anything already delivered.
Search for the employee and add them to the selection.
Then click Next.
Manual enrollment bypasses the flow's normal trigger checks and enrolls the person unconditionally, so you do not need to worry about whether they still match the audience rules.
Step 4: Verify the new enrollment
You will be returned to All Enrollments. Find the new enrollment for that person and click Verify.
Step 5: Choose which messages to send
Pyn shows you every message in the flow for this person, with all of them selected by default. Uncheck the ones they have already received, then click Unpause.
This is the step that stops people getting the same message twice. Say a new hire was enrolled against an original start date, received the first two messages, and then had their start pushed out by four weeks. When you re-enroll them, those two messages are back in the list and selected. Leave them selected and the person receives them a second time. Uncheck them and only the remaining messages are scheduled against the new date.
Everything you leave checked runs on the new start date. Anything you uncheck is not sent.
What to watch for
Deselect duplicates carefully. Message previews are truncated in this dialog, so if two messages look similar, check the delivery detail before unchecking.
Calendar invites. If the flow sends invites and one has already gone out against the old date, uncheck it here and cancel or update the original event directly in the calendar. Pyn will not withdraw an invite that has already been sent.
Late enrollments. If the new start date is close, some messages will already be overdue at the moment you re-enroll. Verify mode gives you control over those in step 5. See Handling late enrollments for how overdue messages behave outside of verify mode.