Rule 12.1A of Standing Orders allows the Parliament (on a motion on the Parliamentary Bureau) to decide that an Acting Convener can be chosen for a committee where the convener is on an extended period of maternity, paternity, parental, adoption or shared parental leave.
The Convener will still be a member of the Committee and hold the office of Convener. This means they can still receive all committee papers (including private papers) so they can keep up-to-date with committee business. However, they cannot participate in committee meetings or any other business of the committee at the same time as the Acting Convener, because that would alter the number and political compostion of members of the Committee.