When to cancel
The holder or EA cancels immediately when the Singapore stint ends. An expired pass need not be cancelled, but an STVP is required while still in Singapore to avoid an overstay fine.
Departure and procedure
Before booking check airline health/visa requirements and home-country embassy entry rules or MFA travel guides.
Cancel through EP eService in myMOM. If still in Singapore, request an STVP for up to thirty days from application, received by email. Show it and a valid passport on departure; cut the old card in half and discard it.
Official source
Written independently from official MOM source material.