Convert Existing Location to Fulfillment Service

[jesse32]

I am trying to convert our custom fulfillment program to the new fulfillment orders workflow. I've been going through the migration document and have come to a stop on step 3: "Opt in to fulfillment orders as a fulfillment service". It does not appear that our program is using a fulfillment service. I am able to make new fulfillment services, but creating one creates a new location which I don't want.

Is it possible to add a fulfillment service to an already existing location?