If you are talking about Rooting the phone, you can root at any time. Disclaimer, It will void the Warranty.
If you are talking about Sim Unlock you need to Contact T-Mobile for a Free Unlock code.
if its paid in full, T-Mobile will send u unlock key within 24 hrs of requesting.
ATTN: SIM unlock team
full name
mobile phone number
phone model
imei
alternate contact phone
email address
copy of paid in full invoice
fax info to 1-813-353-6557
Sent from my SAMSUNG-SGH-I717 using Android Central Forums
Unlocking a phone will only allow you to use it with another provider. It will not let you get rid of the Bloat App. This would take rooting the phone to get Administrator Rights.