You have a couple options!
The most common is to hang onto those dollars until the next market day. Market dollars, or the dollars you take off of your EBT/SNAP card, can ONLY be spent at the market you received them at. Matched dollars, called Double Dollars, can be spent at any market that participates in the Double Dollars program.
If you don’t spend all of your dollars and do not want to hang onto them until the next market, you can return them to your card. For every dollar that goes back on your card, you must return the physical Market Dollar that was given. If the dollars you want to return to your card were matched by Double Dollars, you must also return each Double Dollar match you received for each Market Dollar you return to your card.