Cards & Dice
The complete opposite approach to pure role-playing is to treat social intercourse as a narrative action. The characters use whatever cards they can justify for the situation and attempt to overcome the NPC's resistance.
Social interaction takes time, especially when trying to build trust and convince someone to change their mind. It is best handled as an extended action where the Game Leader sets a target score the characters need to reach in order to achieve their goal. The characters must make a series of actions and repeatedly beat the NPC's resistance.
How long this takes will depend on the situation. In a parliamentary debate each action may represent an hour, but when trapped in a burning building, trying to convince someone to follow a dangerous escape plan, each action maybe just a few seconds long.
Razir has been captured by the town's militia and thrown in the dungeon. He knows that with Boban's help escape will be easy, but he needs to find a way to contact the gnome. With few other options available, he starts to talk to one of the guards in the hope that he can persuade them to take a message to Boban.
The Game Leader decides that passing on messages for prisoners is not unusual for guards, so sets the extended action's target at just 10. However, Razir lacks any money to bribe the guard and the wardens of dungeons are not known for their generosity. So the resistance for the extended action is 3d6+0: 1d6+0 for the Guard path card (because years of experience of being a warden hardens the soul against this sort of request), 1d6+0 for Spite and 1d6+0 Will Power.
Razir examines his cards but is terribly aware that he is weak in this area. All he can come up with is 1d6+2 of Self-Confidence (not allowing himself to be put off by the guard's unreceptive attitude) and 1d6+0 Family Wealth (making credible-sounding promises that the guard will be paid if they deliver the message).
The Game Leader decides that each attempt takes a whole day as there are few opportunities to talk to the guard and they must gain their trust over time.
On the first day Razir scores nine against the guard's 12. Clearly Razir said something wrong as the running total drops to -3. On the second day the guard must have been in a good mood and more receptive as Razir scores a maximum of 14 against the guard's below-average seven. The running total recovers to +4, almost halfway there. As Razir endures another day in prison he hopes that his luck holds and that tomorrow that guard will accept the message.
Should the characters repeatedly fail their action and the extended action's running total reaches twice the original target, the NPC will stop interacting with the character. No more attempts can be made.
Characters and NPCs can benefit from situation bonuses. Characters can also assist each other in their actions in, for example, a good cop / bad cop routine. However attention should be given to the cards used and the character's objective. One character being threatening and the other friendly may be unhelpful when trying to make peaceful first contact with an alien.