As long as the psu is euro ready it's fine to swap input cords.
This is what matters. The "input" voltage requirements
MUST match the voltage supplied through the wall outlet.
What you need to do is read the label on the power supply itself. Verify the input voltage specification says 240VAC. If not, don't use that supply.
Note that these days, the big names in power supplies market their supplies all over the world. Since all ATX Form Factor computers (everything inside your computer case) require the exact same voltages to operate (+3.3VDC, +5VDC, and +12VDC), it is much easier and less expensive for PSU manufacturers to build the exact same supply for worldwide use, and simply design the input for "universal" use. So the only difference is the power cord that is packed inside the box.
Typically, the PSU is able to sense the input voltage and automatically adjust as necessary. On these supplies, the label on the supply will typically say something like 100 to 240VAC.
But there are some power supplies, particularly older ones, that require the user to slide a switch on the back of the supply for 110VAC or 240VAC. There the label may say 110VAC/240VAC and the switch will be labeled in a similar fashion. It is unlikely your Seasonic (because it is a major, global brand) requires manual selection, but look for a switch, and if present, set as necessary.
Last, there are still some power supplies that are manufactured, marketed and sold regionally only. And they may support only one input voltage. So always check the label anyway - just to be safe.
And note the above applies to all AC powered electronics, not just computer power supplies. So if you get a new TV, for example, verify it supports the AC voltage in your country/region.