You can allow another app creator to copy your app. You'll retain control of your app, but the other user can make a copy of it.
When the other user copies your app, they will receive a copy of your entire app and all of its data. Before allowing another user to copy your app, make absolutely certain you are willing to share both you app and all of its data with the recipient. This includes:
Your app definition.
All app data in your worksheets.
All image and file data captured by your app.
Your workflow templates.
Before allowing another app creator to copy your app, you may wish to make a "sanitized" copy of your app that only contains sample data that is safe to share publicly. Then only allow the other user to copy the "sanitized" copy.
You can allow another app creator to copy your app as follows:
Open the app to be copied in the Editor.
Go to the Users tab.
Under SHAREYOURAPP enter the other user's email address.
Click "Add Users ...", which will add the other user to the APPROVED USERS LIST.
Find the other user in the APPROVED USERS LIST and select "Can view definition" from the dropdown menu.
The other user will now see the app under the Shared Apps tab on the other user's My Apps page.
The other user can now click the down arrow next to the app and select "Copy". This copies the app, the app date, and everything associated with the app to the other user's account.
Once the other user has completed the copy, you may wish to remove the other user's email address from APPROVED USERS LIST or to change the user's permissions from "Can view definition" to "Normal user" in the dropdown menu.