the back end file is Access? or SQL server/something else?
I presume the network share is not terminal server or citrix? If not, you are seriously risking corruption - each machine needs it's own copy of the front end on it's local drive and needs to be hard wired to the server (unless using terminal server/citrix in which case the front end will be on the server, but again a copy for each machine in their respective profile directories)
Either way, by ensuring each machine has their own front end copy, you can work on a master copy and update a table in the back end to indicate there are updates available. The front end interrogates the table on a regular basis - might be a form timer, might be an event that happens regularly such as opening a form - and if it picks up there is an update, closes, copies the new front end to the local drive and reopens. Plenty of examples out there how to do this