You can submit a Dependent Care FSA claim over the balance that you have available, but you'll only be reimbursed up to the amount you have in the account (if approved). The remaining balance will be put "on-hold" until your account is funded and then you'll be reimbursed in increments.
That means that each time deposits are made after you’re deducted via payroll, a reimbursement will be immediately initiated until the full amount of your claim has been satisfied or you've reached your annual election.
For example, let's say a child daycare center bill costs $350. Suppose the claim is submitted on 9/14 and your account balance is $100. Assume the contribution from each biweekly paycheck is $100 (supposed your last paycheck was received on 9/11).
For this on-hold claim, it will be reimbursed $100 on 9/14, $100 on 9/25, $100 on 10/9, and $50 on 10/23. Since the total accrued reimbursement is $350 in October, the on-hold claim will be completed.
For claims that are not fully paid off, meaning that there are still On-Hold reimbursements, you will see "Partially Paid" for the claim status.