Systems and methods for facilitating the location of entries in a buffer where a slave device stores information related to an active transaction so that the entries can be removed if the corresponding transactions are canceled. In one embodiment, multiple master devices and multiple slave devices are coupled to a split transaction bus. When a read command is received by a target slave device, the slave device generates an acknowledgment if the slave's command buffer has available entries, or a retry reply if the slave's command buffer is full. The acknowledgment includes a tag which is an index to the buffer location in which the command is stored. If a combined response to the command which is received by the slave device is a retry, the tag, which is included therein, is used by the slave to clear the command from its command buffer.