Although there is no specific button to change the decimal place of a value on your BA II Plus Texas Instrument calculator, you can easily do so with some manipulation of the value with the multiplication button. Simply figure out how many places you want to move the decimal to and then raise 10 to the power of that value. Then simply multiply or divide the value depending on which direction you want to move the decimal to.

Determine how many places you wish to change the decimal point.

Raise 10 to the power of however many spaces you will change. For example, if you wish to change two places, raise ten to the power of two. This will get you 100. This will be your multiplication/division value.

Determine whether you want to change the decimal point to the left or right. If you will be changing the decimal point to the left, divide your value by the value calculated in Step 2. If you will be changing to the right, multiply by the value in Step 2. To divide, simply enter your value, press the "Division" button, enter the value from Step 2, and press enter. To multiply, do the same, but use the "Multiplication" button instead.
References
 "Texas Instruments BA II Plus Calculator"; Texas Instruments Incorporated; 2005