It is possible to move fundraisers between projects.
In order to move a fundraiser from one project to another project, you first have to find the fundraiser in your administration dashboard. On the page fo the fundraiser, you can find a button for changing the project.
Pressing this button will open a pop-up with additional information.
When a fundraiser has already received donations, changing the project will also change the project on the donations for the fundraiser. This should only be done if you either A) have a process in place for updating your records e.g. through a CRM integration that listens to the donation_edited event sent by the webhook. Or if you B) are okay with your internal records diverging from future historical reports being pulled from your dashboard.