So you have the bigger Melita-style No. 4 paper coffee filters for 8- to 12-cup coffee makers and you need a smaller No. 2 filter for your single-cup pour-over cone filter (or 2-cup coffee maker)?
It happens more often than you think. I'm always running out of No. 2's and always have plenty of No. 4's. Mostly because Costco sells a huge pack of the larger filters.
You can just stuff the bigger paper filter into the smaller pour-over cone filter (I have both plastic and ceramic versions).
Or you can trim about an inch off of the larger filter. Use a scissors and follow the curve. It'll save you a trip to wherever coffee filters are sold and help you plow through your endless supply of No. 4's.