I started with McCall's 4652, a knit top with a twisted front and empire seam.
First, I loosely joined the upper and lower bodice pieces with tape.
Next, I made my usual Full Bust Alteration (FBA), spreading the pattern about 1-3/8". You should be doing the FBA with additional tissue under the pattern as shown in the next photo. Otherwise, you will have to reposition everything again like I did. :)
Next, trace the sideseam onto the tissue underneath, as shown in red here. The traced line must be dark enough for you to see under one layer of tissue.
To eliminate sewing a horizontal bust dart and maintain the bust alteration and sideseam shaping, close the dart by rotating the pattern clockwise. Draw the sideseam traced above onto the rotated pattern, as shown in blue here.
Cut away the tissue outside of the traced sideseam. You have now rotated the excess of your bust dart to the sideseam.
Secure your new tissue additions (tape, glue, etc.) and then cut the upper bodice section away using the original pattern shape as your cutting line. True the upper and lower sections as necessary. Add a seam allowance to the top (empire) seam of the lower section. Where I cut already incorporated the seam allowance for the top section, but cut away the SA from the bottom section, which is why I only added a SA back to the bottom section.
Because this top is a 4-way knit, there really isn't any other way to "tissue fit" the knit except by using the actual knit. After cutting one bodice section in the fashion fabric and roughly holding it up to my bust as a test, I decided I still needed additional length in the upper bodice section, since by cutting on the original upper bodice empire line to maintain the shape of that seam for piecing later, I really didn't add any add'l length (which I need) to the bust piece yet. I slashed the pattern under the armhole and spread it vertically to add about 3/4" more to the overall length of the upper section. I have a DD bust cup and this fabric is very stretchy -- your mileage may vary.
The finished top.