If you take the sim card out will it reset everything?

Answer 1

No it will not reset the phone. However, should you take the SIM card with it still in the phone you will not be able to access any of your photos, music or apps that are saved to the SIM card. Taking a SIM card out while a phone is on is not known to do heavy damage to your phone, but excessive removal might make your SIM card unreadable after time.

Answer 2

Removing and reinserting the same SIM card should change nothing on the phone.

The purpose of the SIM card is to provide subscriber information for the phone to the cell tower so that the phone provider knows whose account is in use for the call. Thus they can bill the proper subscriber correctly when they use services that are not unlimited on their plan.

Thus swapping SIM cards for a different one should only change the subscriber information (e.g. phone provider, account number) and should not affect other things (e.g. contact list, calendar events, reminders, photos, ringtones) that are stored elsewhere in the phone.