If a change moves your account to a new day, you might lose access to unfinished daily missions and activities. There could also be a cooldown period for some stores and activities while your account catches up to the new payout times.
Make sure to finish any Daily Activities before you change your payout times.
The payout times for all of your rewards are connected in a fixed way. When you change your Daily Activities Reset time, the times for Squad Arena Rewards and Fleet Arena Rewards will also change to keep the same distance apart.
If you make changes to your payout times around Daylight Savings Time, keep in mind that the clocks will go forward or back one hour.