ST/AI/400 explicitly applies to the abandonment of post and sets out the process to be followed under such circumstances. The Applicant's case is not one of abandonment of post but one of unauthorized absence under ST/AI/2005/3. The mere submission of a medical certificate in support of an absence does not suffice. Said certificate must be approved by the respective Medical Service. This has not been so in the Applicant's case, whose medical situation will be examined by a Medical Board pursuant to ST/AI/2019/1, and her placement on SLWOP is not a violation of her rights.