You currently cannot move pages between sites in Makeswift. You can, however, copy content from one page to another within different sites. Here are steps to do so:
Go to the page you wish to move and navigate into the page builder.
Open a new browser tab and navigate to the Makeswift site you wish to move the original page into.
Create a new page and open the page builder for that page.
Using breadcrumbs, delete all the boxes and elements in the new page.
Go to the tab containing the original page. Using the breadcrumbs, select the first box/section of and copy it using Command/Control + C.
In the second tab containing the new, blank page, press Command/Control + V. You can now click to paste the copied content onto the page.
Repeat steps 5 and 6 for each box or element you'd like to copy over.
Once you have duplicated all the page content, you can delete the original page.
Content pasted into a different site will look identical to the original, but colors and typography will still be connected to the previous site. If a color swatch is updated in the original site, it will affect the second site. You will need to manually add colors and typography and reconnect each element to them.