a blank cheque

idiomPart ofcheque

a blank cheque — idiom

1. a signed cheque with the amount left empty, so the person receiving it can write

1.idiom
Definition

a signed cheque with the amount left empty, so the person receiving it can write in any amount; also used figuratively to mean complete freedom or permission to do whatever one chooses

Example

The manager gave the design team a blank cheque to create the new logo.

Handing someone a blank cheque is risky because they could write any amount.