There are some things to consider when changing an existing POP account to IMAP in Outlook, including:


Deleting emails:

Changing from POP3 to IMAP can delete your existing emails, so you should back up your mailboxes first. 

If you require the outlook data from POP account please go through steps mentioned in below article.


https://www.hostpapa.com/knowledgebase/change-account-pop-imap-outlook/ 


If you want to convert your POP account to an IMAP account, you'll need to remove the current POP3 account (this will not delete any data) and then add the IMAP account.

After you have added your IMAP account and if your mailbox space permits it, you could optionally transfer your current emails, which you downloaded via POP3, and folder structure to your IMAP account. Here we could simpy import the PST file to the newly created IMAP account (this operation can make all your messages and folder structure shown in your Outlook). 


To switch from a POP account to an IMAP account in Outlook, follow these steps below:-


1. Remove the Existing POP Account:

   - Open Outlook.

   - Go to "File" -> "Account Settings" -> "Account Settings."

   - Select the POP account and click "Remove."


2. Create a New IMAP Account:

   - After removing the POP account, click on "New" to add a new email account.

   - Choose "Email Account" and click "Next."

   - Enter your name, email address, and password.

   - Choose "Manually configure server settings or additional server types" and click "Next."


3. Configure IMAP Settings:

   - Select "Internet Email" and click "Next."

   - Choose "IMAP" as your account type.

   - Enter the following details:

     - Incoming mail server: Your IMAP server

     - Outgoing mail server (SMTP): Your SMTP server

     - User Name: Your full email address.

     - Password: Your email account password.


4. More Settings:

   - Click on "More Settings."

   - Go to the "Outgoing Server" tab and check "My outgoing server (SMTP) requires authentication."

   - Go to the "Advanced" tab and set the incoming server (IMAP) to port 993 and use SSL/TLS. Set the outgoing server (SMTP) to port 587 and use STARTTLS.

   - Click "OK" to close the More Settings window.


5. Test the Account:

   - Click "Next" to test your account settings. Ensure that the tests are successful.


6. Finish the Setup:

   - Click "Finish" to complete the setup.