A delivery device (400; 500) for delivering a docking device (1; 501) to a native valve annulus of a patient's heart, the delivery device comprising: a delivery catheter (410; 504) having a first lumen ; and a pusher tool (430; 510) comprising: a pusher (460; 460'; 512) slideably received within the first lumen , the pusher (460; 460'; 512) comprising an elongate tube having a distal portion , and proximal portion , and a second lumen extending from the proximal portion to the distal portion ; a locking mechanism (470; 606) fixedly attached to the proximal portion of the pusher (460; 460'; 512); and a retrieval line (468; 530) extending through the second lumen from the locking mechanism (470; 606) to the docking device (1; 501) to connect the docking device (1; 501) to the pusher tool (430; 510); wherein the locking mechanism (470; 606) includes a rotatable member (473; 536) connected to the retrieval line (468; 530), the rotatable member (473; 536) having a first position that locks the amount of retrieval line (468; 530) that extends from the locking mechanism (470; 606) and a second position that allows the amount of retrieval line (468; 530) that extends from the locking mechanism (470; 606) to be increased or decreased. a delivery catheter (410; 504) having a first lumen ; and a pusher tool (430; 510) comprising: a pusher (460; 460'; 512) slideably received within the first lumen , the pusher (460; 460'; 512) comprising an elongate tube having a distal portion , and proximal portion , and a second lumen extending from the proximal portion to the distal portion ; a locking mechanism (470; 606) fixedly attached to the proximal portion of the pusher (460; 460'; 512); and a retrieval line (468; 530) extending through the second lumen from the locking mechanism (470; 606) to the docking device (1; 501) to connect the docking device (1; 501) to the pusher tool (430; 510); wherein the locking mechanism (470; 606) includes a rotatable member (473; 536) connected to the retrieval line (468; 530), the rotatable member (473; 536) having a first position that locks the amount of retrieval line (468; 530) that extends from the locking mechanism (470; 606) and a second position that allows the amount of retrieval line (468; 530) that extends from the locking mechanism (470; 606) to be increased or decreased. a pusher (460; 460'; 512) slideably received within the first lumen , the pusher (460; 460'; 512) comprising an elongate tube having a distal portion , and proximal portion , and a second lumen extending from the proximal portion to the distal portion ; a locking mechanism (470; 606) fixedly attached to the proximal portion of the pusher (460; 460'; 512); and a retrieval line (468; 530) extending through the second lumen from the locking mechanism (470; 606) to the docking device (1; 501) to connect the docking device (1; 501) to the pusher tool (430; 510); wherein the locking mechanism (470; 606) includes a rotatable member (473; 536) connected to the retrieval line (468; 530), the rotatable member (473; 536) having a first position that locks the amount of retrieval line (468; 530) that extends from the locking mechanism (470; 606) and a second position that allows the amount of retrieval line (468; 530) that extends from the locking mechanism (470; 606) to be increased or decreased. <EOS>