Format change selective cells

If you've got the Euro format created for one value, you could use the format painter [paintbrush on toolbar] to copy it to other individual cells. Double click the format painter (to lock it) then click individually on the cells you want to reformat. When done, click the format painter to unlock it
Alternatively, if you want ALL $ formatted values changed to the new Euro format, click a number with the new Euro format, double click the Format painter then select the row numbers (or column letters, depending on your layout) containing the $ formats to apply the new format.