SPOILERS AHEAD! BE WARNED!
Drop a Calling Card off at a stranger's home. Perhaps they'll return the favour.
Game Instructions: This will allow you to become Acquainted with someone if they accept your card: a polite first approach. Consider sending a message with the card.
Unlocked with Influence < 91
Locked with Acquainted With [friend's name]
A courteous approach
If they accept, perhaps you'll become friends, comrades, or rivals. If they refuse... don't take it personally. Perhaps their social circle is already too large for them; perhaps they wish to reserve some time for their Protégés.
Success Instructions: Becoming Acquainted with someone increases Influence by 1; when your Influence passes 90, you can no longer add Acquaintances until your social circle has been reduced in size.
In Messages Tab
You will receive:
You have sent a Calling Card to [friend's name].