Is it permissible for the one knocking to knock on the door more than three times to wake a sleeper for prayer, knowing that there is a prohibition against seeking permission more than three times?

It is permissible to knock on the door more than three times to wake a sleeper if the knocker believes he has not been heard, because the hadith: "If one of you seeks permission to enter three times and is not granted permission, he should return" applies when it is assumed that the request for permission has been heard. Therefore, for someone who has not heard, there is no harm in increasing the requests for permission in their case. Some scholars have gone so far as to permit increasing the requests if it is known that the permission was not heard, or if it is thought that it was not heard due to distance or other reasons.