The Glendale, Calif., chain has been working with McCann Erickson, Los Angeles, since July 2002 following a review.
IHOP purchased the struggling Applebee's chain earlier this year. The Applebee's account is handled by McCann's New York office and is not involved in the search, the executive said.
IHOP's senior spokesman, Patrick Lenow, said McCann is still the restaurant chain's agency of record. He declined to comment on the review.
The marketer has bounced back in the past two years to become a leader in the family-dining sector. The chain has been riding high on same-store-sales growth for nearly two years, while pricier casual-dining chains have suffered. CEO Julia Stewart has credited menu changes, quality improvement and restaurant remodeling.
While company stock has soared since the Applebee's agreement was announced in June, there are some signs of trouble ahead. Applebee's has been sued by shareholders who say the $1.9 billion price is too low. Sardar Biglari, who owns about 1.4% of the company, has said he'll vote against the acquisition.