are you talking about stored password on Firefox?

1. Click the menu button New Fx Menu and choose Preferences
2. Click the Security panel.
3. Click Saved Passwords... and the Password Manager will open.

See also:

• https://support.mozilla.org/kb/password-manager-remember-delete-change-passwords#w_viewing-and-deleting-passwords

I have an older version of Firefox and it does not have a 'menu' option. I also do not have a stored master password. I need to find a place to change the password it uses to access my email on my employers server.

Sorry, you can't edit a saved password; it needs to be deleted and you should then be offered to save it again when you re-visit that website.

If you are displaying the Menu Bar - File, Edit, View, etc - open Tools > Options -> Security.

Then hit Saved Passwords and click on that website to highlight it, then use the Remove button - make sure that you don't hit the Remove All button by mistake.

An alternative method is this extension - https://addons.mozilla.org/en-US/firefox/addon/saved-password-editor/ - which adds many features, one which is the ability to edit saved passwords.