Paragraphs 6.2-6.4 of the Rules gives the detail on managing rearrangements.
1 The slip dates for 2019/20, for divisions Prem-6, Masters 1&2 are:
14 December, 4 January, 21 March. NB the following important dates:
– 28 March Divisional Cup semi-finals (top 4 in each division)
– 4 April Cup finals
– 10 April Easter
– 8 May Celebration Event
2 There are no official slip dates for Grand Masters/Supervets – to give clubs flexibility to rearrange matches to suit them – however all matches must be completed by 24 April.
3 Clubs are expected to co-operate to rearrange postponed matches on slip dates or on other mutually-agreeable dates within the season. If clubs cannot reach agreement on a date, the league will set one. If it is genuinely not possible for a match to be rearranged before the end of the season, the league will record a 0-0 result, with 0 points per team.