Event Manager Conditional Placeholder for NON-Attributes

In my event-single.php, i’m having trouble getting #_CONTACTPHONE and #_CONTACTURL to only show up if a user has entered those fields in their profile.

It does work with #_ATT:

<?php if ( !empty( $EM_Event->event_attributes['Grade'] ) ) {
	echo $EM_Event->output('<strong>For grades:</strong>   #_ATT{Grade}');
} ?>

However the same format doesn’t work for contact placeholders. how would you write a statement that echos “Phone: #_CONTACTPHONE” only if a phone number is present but echos nothing (including “Phone:“) if a phone number is not entered.