I am unable to come up with the words to explain this action. To turn it the other away would still mean it is in an upright position. Put it down does not sound right either. Please help.
'He flattened the calendar to the table'.
Example 'John turned, and flattening the calendar to the table, turned to Kathleen. Looking into her shining eyes, he said quietly 'Kathleen, whatever the dates are - it doesn't matter. We're going to bring up this baby, and do it together, don't you worry...'
If you want more urgency you could use 'smashed', like this:
Example 'John smashed the calendar to the table with a bang, turning to Kathleen with flashing eyes. Kathleen! I won't hear this again! It's our baby and we're keeping it!'