I give advice to them that first I talk to the group and tell them that she is in some problem that's why she did not attend the rehearsal or some other reason so you don't annoyed with her or secondly i 'll tell that if u r in some problem or u r not able to come to the rehearsal so u should tell ur rest of the group member from this I conclude that understanding & trust is very imp in between frnds or group understanding & trust make easier every situation