Hi Colette, yes. Any changes made to flow steps after the wait step that they're in will go as they're written at the time that they leave the wait step and move to the next step (if that makes sense).
If you change the duration of the wait step while someone is in it, they will exit the wait step in the timeframe that it was when they originally entered it. Example, when someone enters a wait step it is for 2 weeks. You decide mid-wait step that you want your email to go at 1 week instead of at the end of the 2 week wait step. Changing the wait step will only impact people who aren't currently in the wait step.
Hope that helps, sorry it's a little confusing!
A couple of clarifications -
Your email must be approved for this to work.
If this is a batch campaign that is already in the process of executing, your email change will not work because Marketo has already taken the email and done things with it.
Removing people from Wait Steps - if you wanted to take out people who were stuck in 2 weeks and then put the in 1 week, you would have to Remove from Flow and then redirect those people to 1 week with a separate campaign.
what do you mean by "Marketo has already taken the email and done things with it"? I have a campaign in a wait step right now. When we started the program running, it was going to "Send Email "3 tomorrow morning at 10. I have not updated the email and replaced it with "Send Email 3b".
When the Wait step ends, is it going to send my new email, or send what was programmed to be next when the program started? Very curious to know!