Hi @AnnieB1
Yes - there is a way.
Instead of stopping your share (or the whiteboard) click on the New Share (green button) to switch your share to either your Screen Share or your Whiteboard.
If you switch away from your whiteboard and back again later, your whiteboard contents will still be there.

If this answers your question please click Accept as Solution.
If you need any more help just post back here.
Rupert