.

[ca88313]

.

[themeandvariation]

It is Already in C# minor.. So play as written.  
But i also see that your wrote 'Db "major"..' So if you want it in 'major' - you'll have to rewrite the composition itself..
Or, if you wanted to use a major scale - Db major.. one could use That scale - to transpose the piece to Bb minor.  (not sure why i responded here, this is pretty whacky..

please choose 0ne of the options, or explain the reason of your intention.
T.

ps..the 2nd movement is already in Db major..

[ca88313]

.

[themeandvariation]

The piece you posted is not simply transposed.. It has been harmonically changed.. and not only to make the c#m chord sound d flat major, but there are other tweaks, some of which don't seem to work in the context set up at all.. But i get that 'flavor' difference that you are attracted to.You will either have to get the score from the one who posted it, or sound it out yourself, and piece it together , like a puzzle.

There are pieces that are reminiscent  of this though, … something Like Chopin middle section of Fantasy impromptu - (where it goes into d flat major - ) or the raindrop prelude - (also in  Dflat major) or the B flat minor sonata - slow movement excerpt - (where it goes into Dflat major) .
Im sure that others could come up w better examples here..

[ca88313]

.