Merging contacts between iCloud and Exchange accounts

Hello, community.

Here's the problem that I'm experiencing. For a year I was employed at a large company that used a Microsoft Exchange server. Naturally, I added an Exchange account in order to have access to corporate database of contacts and in order to have my calendar synced.

However for some unknown reasons, some of my new contacts that I have created during that period instead of being saved to my iCloud account were saved to that Exchange account. When I stopped working at that company, I immediately deleted the Exchange account (especially because it was deleted on their server and iPhone would ask me for a password, which would never be correct because it doesn't exist). After I've deleted that account I noticed that I'm basically missing around 50% of new contacts entries that I've created for the past year.

However that account is still remaining on my Mac and my iPad and I can still access it. It tells me that the password is incorrect, but I can still see and edit all the contacts.

Question: Is there some nice and handy way to transfer some of the entries from the non-existent Exchange account to iCloud account? How to avoid this situation in the future?

Thanks in advance.