i have the below given time interval options in a dropdown (those are strings)

```
<select name="CSSAtapsClient[client_time_window][0]" id="client_time_window_0">
<option value="5702">7am - 10am</option>
<option value="5703">10am - 1pm</option>
<option value="5704">12pm - 3pm</option>
<option value="5705">3pm - 6pm</option>
<option value="5706">6pm - 9pm</option>
<option value="5707">7pm - 10pm</option>
<option value="5708">9pm - 12am</option>
<option value="5709">12am - 7am</option>
</select>

```

I need to convert these intervals for a specific GMT time zone. for example lets say its in GMT +8 and i need to convert it to GMT +10 and it can be done by adding 2 hours.

so if the given time interval is, **7am - 10am** (GMT +8) it should come as **9am - 12pm** (GMT +10)

What is the best way to convert this kind of a time interval ? The issue i am seeing here is its a string (time interval).

Appreciate an early reply.

**EDIT 1**

I am converting to only Australian states so there is no chance of getting a day as difference when converting. pls check this link <http://www.timebie.com/tz/australiatimezone.php>