Ask your jungle if they want the lane.
If no, farm the lane defensively, focus on never extending and freezing the lane as much as possible. If you're an AP Support, build wave clear (Flat AP, CDR, Luden's Echo). If you're a Tank Support, build siege control (Zz'rot Portal, Banner of Command). The goal is to hold the lane as long as possible.
If they want the lane, play like a duo lane, though a tad more aggressively than normal. Junglers trade relatively well early game in my experience, and they tend to fall off where carries get strong, so you need to take advantage of the moment and fight while your Jungler-now-bot-laner is stronger than the enemy carry.