I don't have any spare space to backup all the data
You want to change the basic format of your hard disk without backing up your data!!? I highly recommend you don't do anything that changes the format of a hard drive, even single partitions, without having any data you want to keep in at least one other permanent data store. In any event, you can't convert dynamic to basic without reformating. It may be possible upon deletion of the dynamic format to recover and write a partition table using partition recovery software, but who would take that chance?