If you have savvy end users then you could let them install updates... but I
wouldn't leave this type of update to them.
Either way BEFORE YOU START make backup copies of everything!!!
Create a new database and call it TRAVEL or whatever you want.
Navigate to the forms section and right click in the database window. Choose ||IMPORT|| and navigate to your current database location. Select the form(s) using the control key, and import them into your new database. Repeat this in the users database (if the form names are consistant then it will copy them in with a number appended to the end of the form name: frmUserInformation would become frmUserInformation1 for example).
Then you can pick and choose what to update by renaming the originals as a backup: frmUserInformationBAK for example and then change the name of frmUserInformation1 to frmUserInformation. This should update the database to include any changes that you made in the form WITHOUT affecting records. If you have changed ANY information about field names or associations then you will need to make the changes to your existing table structure or you will have a mess.
My advice is to DOCUMENT DOCUMENT DOCUMENT every step you make.
It is much easier to do then to explain..
Good luck, hope this was helpful JerseyBoy
Remember: self-praise is no recommendation