I would ask help from someone knowledgeable on MS Hosted exchange mailboxes:
I have an older exchange mailbox, call it Mailbox A. This mailbox contains an extensive calendar and contacts list. I have a new exchange mailbox, call it Mailbox B. It has no contacts or calnedar as of yet.

I want to transfer all my contacts and calendar form Mailbox A to Mailbox B; ending with Mailbox A having a blank calendar and zero contacts and Mailbox B having all the contacts and calender now in Mailbox A.

I have tried right clicking "Contacts - Mailbox A"; COPY FOLDER; then selecting Mailbox B - Contacts. This creates a second folder called Contacts-Mailbox B. Thus I end up with one folder named Contacts-Mailbox B containing all my contacts (this folder is deleteable) and another folder named Contacts-Mailbox B containing NO contacts (this folder is NOT-deleteable).

What is the correct procedure for calendaer and contacts?

Thank you kindly for your help