To force a bill out of committee, a/an blank petition must be signed by a majority of the representatives.

The full sentence is as follows:
To force a bill out of committee,  A DISCHARGE petition must be signed by a majority of the representatives. 
A discharge petition refers to a petition that is used in the house of representative to force a bill out of the committee unto the floor of the house for a vote. For the petition to be successful, 218 members of the house have to vote in its favor.