A method implemented by a client device (102; 202; 302; 402) that initiated a voice communication session (206; 306; 406), the method comprising: while the voice communication session is in an on hold status: monitoring an audio stream of the voice communication session for an occurrence of a human voice speaking into the audio stream; in response to detecting the occurrence of the human voice during the monitoring: sending a response solicitation signal (204; 304) as input to the audio stream; monitoring the audio stream for a response to the response solicitation signal; determining whether the response to the response solicitation signal is a human response that is responsive to the response solicitation signal based on determining whether the human response corresponds to at least one predicted response to the response solicitation signal, wherein the method is characterised in that it comprises: when it is determined that the response is a human response that is responsive to the response solicitation signal: causing user interface output to be rendered that is perceptible by the calling user and that indicates an end of the hold status, wherein the user interface output includes one or more of: audio output, vibration output, and visual output; and when it is determined that the response is a human response that is not responsive to the response solicitation signal: identifying one or more voice characteristics of the voice which spoke the response and/or one or more words spoken by the voice for use in determining not to send a response solicitation signal when one or more future occurrences of the one or more voice characteristics and/or one or more words are detected. monitoring an audio stream of the voice communication session for an occurrence of a human voice speaking into the audio stream; in response to detecting the occurrence of the human voice during the monitoring: sending a response solicitation signal (204; 304) as input to the audio stream; monitoring the audio stream for a response to the response solicitation signal; determining whether the response to the response solicitation signal is a human response that is responsive to the response solicitation signal based on determining whether the human response corresponds to at least one predicted response to the response solicitation signal, wherein the method is characterised in that it comprises: when it is determined that the response is a human response that is responsive to the response solicitation signal: causing user interface output to be rendered that is perceptible by the calling user and that indicates an end of the hold status, wherein the user interface output includes one or more of: audio output, vibration output, and visual output; and when it is determined that the response is a human response that is not responsive to the response solicitation signal: identifying one or more voice characteristics of the voice which spoke the response and/or one or more words spoken by the voice for use in determining not to send a response solicitation signal when one or more future occurrences of the one or more voice characteristics and/or one or more words are detected. sending a response solicitation signal (204; 304) as input to the audio stream; monitoring the audio stream for a response to the response solicitation signal; determining whether the response to the response solicitation signal is a human response that is responsive to the response solicitation signal based on determining whether the human response corresponds to at least one predicted response to the response solicitation signal, wherein the method is characterised in that it comprises: when it is determined that the response is a human response that is responsive to the response solicitation signal: causing user interface output to be rendered that is perceptible by the calling user and that indicates an end of the hold status, wherein the user interface output includes one or more of: audio output, vibration output, and visual output; and when it is determined that the response is a human response that is not responsive to the response solicitation signal: identifying one or more voice characteristics of the voice which spoke the response and/or one or more words spoken by the voice for use in determining not to send a response solicitation signal when one or more future occurrences of the one or more voice characteristics and/or one or more words are detected. when it is determined that the response is a human response that is responsive to the response solicitation signal: causing user interface output to be rendered that is perceptible by the calling user and that indicates an end of the hold status, wherein the user interface output includes one or more of: audio output, vibration output, and visual output; and when it is determined that the response is a human response that is not responsive to the response solicitation signal: identifying one or more voice characteristics of the voice which spoke the response and/or one or more words spoken by the voice for use in determining not to send a response solicitation signal when one or more future occurrences of the one or more voice characteristics and/or one or more words are detected.