In the event you need to change the next order number from Service Pro, use the following format. Make sure that you are using the PowerShell; this will not work in Command Prompt.
curl.exe -v -X POST 'https://spxtest.net/service/api/SystemCounters/UpdateCounter' --data '{"Name":"OrderNumber","Counter": XX}' --header "Accept: application/json" --header "Content-Type: application/json" --header "APIKey: ..." --header "SK: ..."
The XX listed above would be the number you want to change this to. Next to APIKey and SK are ... - you should have this data already.