Can the IRS change my installment agreement?

If you have missed a payment on your IRS installment agreement, you will be sent a form CP 521. This notice will include a deadline for you to make the late payment, and it may also include details about fees and interest you may be charged. The IRS can change your installment agreement if you fail to make payments. This CP 521 is the first notice that a change may be pending. In order to maintain control over your agreement, pay the past due amount by the date noted on the CP 521. Failing to act may lead the IRS to send your debt to collections and alter your agreement.

For more info, read Why You Should Avoid the IRS Installment Agreement.