Yes, you can change the options under the Environment setting for your alarms, but here's another way that doesn't require changing the "default" setting:
You can change the notify alarm on any meeting appointment by "right-clicking" the appointment on your calendar and selecting "alarm". Then in the alarm dialog box change the default setting for this appointment to the amount time (hours or minutes) you will need. This is a great feature if you have an appointment outside the office and the "10 minute" default setting won't work for an appointment across town! Also, you have the option to keep your "default setting for those appointments that don't require extra notification time
Regards,
Stars