To Place a Stacked Fraction with Auto-Stacking Off

Select Text Styles (Drawing > Annotate > Text dialog launcher).
The Text Styles dialog opens.
On the General tab, turn off Fractions.
Select the Place Text tool.
The Text Editor window opens.
Right-click in the Text Editor window and select Insert Stacked Fraction.
The Insert Stacked Fraction dialog opens.
Enter the numerator and denominator values in the respective fields.
(Optional) Select the bar type from the Type drop-down list and the alignment from the Alignment drop-down list.
Click OK.
Enter a data point to place the fraction.
Note: The Text Editor window supports fraction characters defined in RSC fonts. To enable this feature, the capability setting CAPABILITY_WORDPROCESSOR_USE_RSCFRACTIONS must be set. If a fraction character is present in the font, the stack fraction is replaced by this character.

If you have the fraction already placed in the Text Editor window, you can select it and choose the Make Stacked Fraction from it's right-click menu. Then, in the Insert Stacked Fraction dialog that opens, you can make the desired changes and click OK to place the fraction as a stacked fraction.