I went through a similar change in payment dates about 25 years ago to be honest , from weekly to monthly pay , The company gave us thechance to have an interest free loan to accomadate any problems we would encounter , You would be wise to ask them your company is offering any assitance similar to this, Failing that discuss it with your bank for a free overdraft facility just in case you needed to use it , better to plan ahead and have something in place than nothing at all,