private async Task <List <BuilderParticipant> > AddPersonParticipantsWithOidsAsync(
            Invitation invitation,
            List <BuilderParticipant> meetingParticipants,
            List <ParticipantsForCommand> personParticipantsWithOids)
        {
            var personsAdded = new List <ParticipantsForCommand>();

            foreach (var participant in personParticipantsWithOids)
            {
                if (InvitationHelper.ParticipantIsSigningParticipant(participant))
                {
                    meetingParticipants = await AddSigner(
                        invitation,
                        meetingParticipants,
                        participant.InvitedPerson,
                        participant.SortKey,
                        participant.Organization);

                    personsAdded.Add(participant);
                }
            }

            personParticipantsWithOids.RemoveAll(p => personsAdded.Contains(p));

            var oids    = personParticipantsWithOids.Where(p => p.SortKey > 1).Select(p => p.InvitedPerson.AzureOid.ToString()).ToList();
            var persons = oids.Count > 0
                ? await _personApiService.GetPersonsByOidsAsync(_plantProvider.Plant, oids)
                : new List <ProCoSysPerson>();

            if (persons.Any())
            {
                foreach (var participant in personParticipantsWithOids)
                {
                    var person = persons.SingleOrDefault(p => p.AzureOid == participant.InvitedPerson.AzureOid.ToString());
                    if (person != null)
                    {
                        invitation.AddParticipant(new Participant(
                                                      _plantProvider.Plant,
                                                      participant.Organization,
                                                      IpoParticipantType.Person,
                                                      null,
                                                      person.FirstName,
                                                      person.LastName,
                                                      person.UserName,
                                                      person.Email,
                                                      new Guid(person.AzureOid),
                                                      participant.SortKey));
                        meetingParticipants = InvitationHelper.AddPersonToOutlookParticipantList(person, meetingParticipants);
                    }
                }
            }

            return(meetingParticipants);
        }