Addition to Payment Plan

[optx103]

Hello,

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!

[JotikaT2]

She will need to log in to her account with the IRS and make the changes.  See the section titled How do I review or revise an existing plan?

IRS site to apply for installment plan or change an existing plan 

[optx103]

We couldn't see anything very useful on that site. Only modification of payment amount and payment date. No option to request addition of a new balance. So wondering if anyone knows if IRS is still automatically rolling new balances into existing payment plans ( bullet point #3 here). Thanks.