A family member started an installment agreement last year that is mostly paid off. This year is still challenging and she wants to add a chunk of 2020's tax due to the plan. Question is, what's the best way of doing this, preferably without defaulting (which apparently occurs when a new balance comes due)? I can't seem to find whether the IRS is still automatically adding new balances to existing payment plans, as for 2019. Thanks!
