28 Del. C. § 1549: Call procedure.

(a) Players who unintentionally put fewer chips into the pot than are needed to call must complete the call or withdraw the partial bet in full. If action has taken place, the player is responsible for completing such player’s bet, even if the player might have been unaware of the raise. Players may assemble chips in front of them before acting. A player makes a bet if such player pushes assembled chips forward or releases chips into the pot at a sufficient distance from the player to make it obvious that the intent is to bet. If the situation is unclear and a player allows the dealer to pull the player’s chips into the pot without making an immediate objection, it is a bet. A player must place the entire bet in front of the player at 1 time. Unless a player has placed the amount of chips required to call a bet and to signify a raise, the player may not place additional chips for a raise.

(b) If a player calls but places a value of chips into the pot that is larger than the bet, it must be regarded as a call unless the player announces a raise. The player may clarify an apparent call as a raise only if no other player behind such player has placed chips into the pot or announced a call or raise.