This might help answer your questions above and also what has been given to you via the contract terms & conditions. All in all, you will still need to speak with agency in regards to early terminations. Hence, once terminated either they will be send home or transfer maid to those applicants needed maid on immediate. Process wise? Subject to what's agreed between you and agency as well as your maid. Also you/agency are to let her know of your early termination to be fair with her.
As far as I know, employer terminate early contract or return maid because of some issues.
https://www.mom.gov.sg/employment-agencies/refund-of-ea-service-fee