The attack took place at about 9:30am on Thursday December 29, when a man entered business premises in High Street, Westtown, Dewsbury, and made demands for cash.ã€€
The shop assistant refused and the suspect, who was "believed to have been carrying a knife", fled empty handed.ã€€
Police are looking for a man wearing dark clothing who fled onto St John's Parade.ã€€
PC Luke Mitchell, of Huddersfield CID, said: "This was undoubtedly a terrifying attack on a lone member of staff who has worked in the community for many years.ã€€
"CCTV enquiries have shown that there were a number of members of the public in the area at the time and I am appealing for them to come forward to assist police with our enquiries."ã€€
Anyone with any information is asked to call PC Luke Mitchell in Huddersfield CID via 101, quoting crime reference 13160757147, or the independent charity Crimestoppers on 0800 555111.