If you’re one of those taxpaying parents who loves the big refund check after filing, you may want to take action Monday. That’s the final day to request your enhanced child tax credit as one lump sum rather than in the form of a monthly check, according to the IRS.

Those who choose to unenroll from the monthly payments must do so “3 days before the first Thursday of next month by 11:59 p.m. Eastern Time,” the IRS says. That means individuals who want all of the credit applied as a one-time credit must take action by June 28 in order for the changes to be recorded prior to the July 15 payout window.

However, once the initial deadline passes, taxpayers can still opt out of some — but not all — checks, provided they do so by the following dates:

August: Unenrollment deadline is Aug. 2, payment date on Aug. 13
September: Unenrollment deadline is Aug. 30, payment date on Sept. 15
October: Unenrollment deadline is Oct. 4, payment date on Oct. 15
November: Unenrollment deadline is Nov. 1, payment date on Nov. 15
December: Unenrollment deadline is Nov. 29, payment date on Dec. 15

According to the IRS, “unenrollment is a one-time action. You will be able to re-enroll starting in late September 2021.”

The IRS says, some people may also want to unenroll from monthly checks if they “expect the amount of tax you owe to be greater than your expected refund when you file your 2021 tax return.” Because the payments are being paid in advance, “every dollar you receive will reduce the amount of Child Tax Credit you will claim on your 2021 tax return.”

The enhanced child tax credits are part of President Joe Biden’s $1.9 trillion coronavirus relief package signed into law earlier this year. Eligible families can receive as much as $300 per month — $3,600 annually — for each child under the age of 6. The advance tax credit payments will be $250 per month — $3,000 annually — for each child between the ages of 6 and 17.

The amount is determined based on the parent’s 2020 or 2019 tax return, whichever is the last one filed on record with the federal tax agency.

However, people can register for the program with the IRS even if they did not fully file their taxes. The administration launched the website childtaxcredit.gov with details for potential recipients.

The first batch of payments, for those choosing to take them monthly, will be distributed July 15.

Last week, the IRS launched an online tool that allows taxpayers to check their eligibility.

Taxpayers are eligible to receive the full amount if their income is $75,000 or less for single filers, $112,500 or less for heads of households, or $150,000 or less for married couples filing jointly, as well as qualified widows or widowers.

Those with incomes higher than those thresholds will get reduced amounts until they are phased out entirely, at $400,000 for married couples filing a joint return and $200,000 for all other filing statuses.

An estimated 39 million families are expected to receive the expanded credits.

The latest information about the expanded child tax credits can be found at IRS.gov/childtaxcredit2021.