There are many alternate tunings for the ukulele.
The most common tunings are the modern standard ‘GCEA’, and the more traditional ‘ADF#B’, which is merely a step higher than the more modern tuning, meaning all notes and chords on it are merely a whole step above what they are in an ADF#B tuning (G chord becomes A chord, F# becomes G#, etc.)
Alternate tunings have multiple purposes: they can make chords less complicated to play, which can make playing with a slide significantly easier, they can make one note easier to play, which on the ukulele usually means retuning the re-entrant string to another note, and they can serve other purposes as well.
Firstly, we shall retune your ukulele to an alternate ‘open tuning’ which will produce a major chord (C, in this case) when all open strings are strummed.
Drop your A string down to a G, the same note as your re-entrant.
Now strum the strings. You are playing a C chord. Put one of your fingers across all strings at the first fret and strum. You have just played a C# chord. If you place your finger across the 2nd fret, you will get a D chord, 3rd, Eb, 4th E, etc. etc.
This tuning, however, alters the way other non major triads are played, causing you to re-learn your chord shapes if you wish to use this tuning for much.
Now we will tune your ukulele to ADF#B if you have never done so before. Don’t worry, your strings won’t break as long as they are in good condition (and if they are in bad condition, they still shouldn’t break). Do this by tuning each string up one whole step (two frets) from what it is tuned to in GCEA tuning. The easiest way to do this from GCEA tuning is tuning the re-entrant G up to the A using your A string as a reference, and then tuning all of your other strings off of the Re-entrant A that you have just tuned.
This tuning is said to often produce a brighter sound in some ukuleles, especially smaller ones, such as sopranos and some concerts, as it supposedly is more fit to a ukulele’s body’s optimal tonal range of amplification.
I personally find that an ADF#B tuning may be somewhat brighter sounding, but that it is not a significant difference, and therefore I generally stick to the tuning that I am most familiar with, GCEA.
Have some fun strumming around in this tuning: you can use the same chord shapes as you do in GCEA, and they will just be transposed up a step.