Linq: How do I create a loop that saves at the end of each loop sequence?

The code below loops through 50 Contact records and updates each record with migrated = true.

The "actual" Saving occurs only when the loop has gone through all 50 records.

However, if record number 19 fails to create in the Target System, the loop breaks and records 1 to 18 will never get updated (with migrated = true) in the Source System.

How do I create a loop that saves at the end of each loop sequence?

var sourceconatcts = (
    from c in xrm.ContactSet
    join i in xrm.IncidentSet on c.ContactId equals i.CustomerId.Id
    where (c.new_migrated != true)
    select c).Distinct().Take(50).ToList();
        foreach (var contact in sourceconatcts)
        {
            // Code that creates a record in the target system has been removed
            // Update Source System that record has been migrated successfully
            contact.new_migrated = true;
            xrm.UpdateObject(contact);
        };
    xrm.SaveChanges();