As far as I know, the MS-9050 is and was only ever available as the MS-9050UD. The MS-9200 and 9600 panels once had the non-UD (universal-dialer) but those are older software and hardware versions.
If this system is in current use for life safety and it says everything is full, A. don't do the work if you're not qualified, and B. unless you've removed old points to make room for new ones, you'll need a panel with more point capacity to add more than 50 points.
To reprogram the MS-9050UD, do the following:
Open this link to the manual directly from Fire-Lite: http://www.firelite.com/CatalogDocuments/52413.pdf
. Read the programming chapter carefully before doing any of this so you have a much clearer picture of what each programming option can and can't do.
With the power OFF
Install all the field devices and set their addresses in the configuration you want it (01-50), and connect the SLC to the panel. Connect AC and then batteries and let the system initialize. Ignore any "missing point" or "wrong type" troubles because the panel is still running the old configuration.
Access the programming menu with the appropriate access code.
Enter the programming menu and select option 1 "AUTOPROGRAM."
This will ERASE the current hardware configuration saved in the panel's memory.
When it runs through the autoprogramming process, the panel will scan each device on the SLC loop and determine it's type and assign all the other settings (like zone assignment) to default. Any previously installed devices that no longer exist should be removed from memory automatically (if not, there's a separate programming screen to delete points).
Once it's done, you can use the point programming menu to edit names and zones and any mapping rules you want to implement. Note that the dialer settings, NAC sync, etc, will not be reset to default unless this is the panel's first startup. You'll have to do that manually.
Hope this information is helpful!!