Pause a person in a smart campaign flow with the handy wait step.
Notice how you can type in natural language like “4 hours.” Do not, however, abbreviate the words (i.e., 4 hrs). The smart campaign would still run, but the wait step would be ignored.
Changing the duration of a wait step will not affect people that have already entered it. For example: you have a wait step for 5 days, a person enters it, you then change the wait step to 7 days - that person will still only wait the original 5 days before advancing to the next flow step.
There are three main ways to use a wait flow step: