Apparatus for use with a tissue of a subject, the apparatus comprising: a tissue anchor, comprising an engaging head (44, 46) and a tissue-coupling element, transluminally deliverable to the tissue, and reversibly anchorable to the tissue; and an anchor-manipulation tool having a distal portion transluminally deliverable to the tissue, the anchor-manipulation tool comprising: at the distal portion of the tool, an anchor-engaging element and an anchor-engaging-element actuator, and at a proximal portion of the tool, a controller configured to control the anchor-engaging-element actuator, the apparatus having at least two states, comprising: an uncoupled state in which the anchor-engaging element is not in contact with the tissue anchor, and a coupled state in which the engaging head (44, 46) is configured to at least in part inhibit movement of the anchor-engaging element away from the tissue anchor, the anchor-engaging-element actuator being configured to facilitate transition of the apparatus from the uncoupled state to the coupled state, and the anchor-manipulation tool, in at least one of the at least two states, being configured to apply a de-anchoring force to the tissue anchor; characterized in that the coupled state is an articulatably-coupled state, with the distal portion of the anchor-manipulation tool being configured to be deflectable with respect to the tissue anchor when in the articulatably-coupled state. a tissue anchor, comprising an engaging head (44, 46) and a tissue-coupling element, transluminally deliverable to the tissue, and reversibly anchorable to the tissue; and an anchor-manipulation tool having a distal portion transluminally deliverable to the tissue, the anchor-manipulation tool comprising: at the distal portion of the tool, an anchor-engaging element and an anchor-engaging-element actuator, and at a proximal portion of the tool, a controller configured to control the anchor-engaging-element actuator, the apparatus having at least two states, comprising: an uncoupled state in which the anchor-engaging element is not in contact with the tissue anchor, and a coupled state in which the engaging head (44, 46) is configured to at least in part inhibit movement of the anchor-engaging element away from the tissue anchor, the anchor-engaging-element actuator being configured to facilitate transition of the apparatus from the uncoupled state to the coupled state, and the anchor-manipulation tool, in at least one of the at least two states, being configured to apply a de-anchoring force to the tissue anchor; characterized in that the coupled state is an articulatably-coupled state, with the distal portion of the anchor-manipulation tool being configured to be deflectable with respect to the tissue anchor when in the articulatably-coupled state. at the distal portion of the tool, an anchor-engaging element and an anchor-engaging-element actuator, and at a proximal portion of the tool, a controller configured to control the anchor-engaging-element actuator, the apparatus having at least two states, comprising: an uncoupled state in which the anchor-engaging element is not in contact with the tissue anchor, and a coupled state in which the engaging head (44, 46) is configured to at least in part inhibit movement of the anchor-engaging element away from the tissue anchor, the anchor-engaging-element actuator being configured to facilitate transition of the apparatus from the uncoupled state to the coupled state, and the anchor-manipulation tool, in at least one of the at least two states, being configured to apply a de-anchoring force to the tissue anchor; characterized in that the coupled state is an articulatably-coupled state, with the distal portion of the anchor-manipulation tool being configured to be deflectable with respect to the tissue anchor when in the articulatably-coupled state. an uncoupled state in which the anchor-engaging element is not in contact with the tissue anchor, and a coupled state in which the engaging head (44, 46) is configured to at least in part inhibit movement of the anchor-engaging element away from the tissue anchor, the anchor-engaging-element actuator being configured to facilitate transition of the apparatus from the uncoupled state to the coupled state, and the anchor-manipulation tool, in at least one of the at least two states, being configured to apply a de-anchoring force to the tissue anchor; characterized in that the coupled state is an articulatably-coupled state, with the distal portion of the anchor-manipulation tool being configured to be deflectable with respect to the tissue anchor when in the articulatably-coupled state.