European Professional Football Leagues memorandum of understanding with UEFA which ends on 31st May 2022
While it applies to Top Division games in the past it also covered National Cup games
https://www.uefa.com/MultimediaFile...aorg/Leagues/02/55/15/63/2551563_DOWNLOAD.pdf
3.8. Subject to Clause 3.9, to ensure that EPFL Member Leagues abstain from scheduling top division matches on dates which are reserved for UEFA club competition matches, in accordance with the UEFA Match Calendar.
3.9. Without prejudice to the generality of Clause 3.8, EPFL Member Leagues may be allowed to schedule matches on dates reserved for UEFA club competitions when no other date could be found under the following exceptions:
Top division matches, which had to be postponed due to force majeure or to other reasons beyond the reasonable control of the concerned EPFL Member League, may be rescheduled on dates reserved for UEFA club competition matches, upon agreement with UEFA, when it appears that no real alternative exists.
If such matches are not to be broadcast domestically and/or internationally, no restriction applies as to their kick-off time.
If such matches are to be broadcast domestically and/or internationally, they shall be scheduled in such a way that they are terminated at least 15 minutes before the kickoff of the UEFA club competition matches, subject to UEFA’s approval on a case by case basis.
The following non-exhaustive list of circumstances are considered to be “out of the control” of the concerned league:
Adverse weather conditions;
Strike and civil unrest;
Sudden unavailability of a stadium;
Decision of a competent state authority to move a match;
Participation of clubs in the FIFA Club World Cup;
When UEFA itself reschedules matches at dates which are reserved for domestic competitions; and
If there are no alternative dates available for a club to meet its fixture commitments in order to avoid that a player has to play 2 matches within 72 hours due to the scheduling of a competition sanctioned by FIFA, UEFA and a National Association.
In such cases, the UEFA Administration must be consulted at least 3 days before the decision to reschedule the domestic match in question has to be taken by the concerned EPFL Member League with a view to coming to an agreement on the date and time for such match.
UEFA shall consider requests for kick-off time slots overlapping with UEFA competition matches on a case-by-case basis and undertakes to strive to find a positive solution, depending on all circumstances of each individual case. Specifically, the Western European time zone is a factor to be taken into consideration for the granting of such requests.
