First lady Michelle Obama has postponed a campaign fundraiser that had been scheduled for Tuesday at the Houston home of billionaire and former Enron executive John Arnold, her office announced today.

The White House advisory cited “scheduling conflicts” for the change. Dana Guefen, a co-chair for the event, declined to comment to ABC News on why the event was moved.

Obama was to also appear at an earlier, larger fundraiser at the Westin Oaks in Houston. She was slated as the keynote speaker at both events.

Arnold, 37, one of the 400 richest Americans according to Forbes, was one of Barack Obama’s top financiers in 2008, bundling between $50,000 and $100,000 in contributions for his election campaign, according to the Center for Responsive Politics.  He has personally given the legal maximum — $5,000 — to Obama for 2012, records show.

An Obama campaign official said the Houston fundraisers would be rescheduled as soon as possible. They were to benefit the Obama Victory Fund, a joint account run by President Obama and the Democratic National Committee.  Ticket prices for the Arnold event ranged from $10,000 up to $35,800, the combined legal maximum.

The first lady will still travel to New Orleans Tuesday to attend a campaign fundraiser and an event for her “Let’s Move” initiative, the White House says.